• Title/Summary/Keyword: Blast efficiency

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An Experimental Study on the Engineering Properties of Concrete According to the Replacement Ratio of Blast-Furnace Slag (고로슬래그 미분말 대체율에 따른 콘크리트의 공학적 특성에 관한 실험적 연구)

  • 송민섭;장재봉;김갑수;윤종기;김재환;김무한
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2003.05a
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    • pp.5-8
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    • 2003
  • As a part of efforts to obtain high quality and economical of efficiency of concrete, blast-furnace slag has been utilized by means of cement replacement. Therefore superior performance can be ensured, environmental pollution can be prevented and economical advantage can be obtained with utilization by cement replacement. But the studies on the blast-furnace slag are not systematic and reasonable. So, it was planed that basic data in regard to technique of manufacturing and economic improvement of concrete is showed with experimental comparison and investigation of engineering properties of concrete utilizing blast-furnace, industry by-product, as cement replacement in this study.

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Analysis of SLF Interruption Performance in self-blast Gas Circuit Breaker (복합소호형 가스 차단기의 SLF 차단 성능 해석)

  • Park, Jin-gun;Ahn, Hee-sup;Choi, Jongung;Kim, Younggeun;Cho, Heayong
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.9
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    • pp.24-32
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    • 2020
  • A self-blast type gas circuit breaker has been studied in this study to improve efficiency of interrupting performance of short line fault(SLF). Hot gas flows of gas circuit breaker have been simulated to evaluate interruption performance using CFD. Design parameters such as various types of expansion chamber and nozzles are suggested by using simulation results. Simulated results and experimental ones are compared with previous (ones that of in under development and with capacitor) GCB. Modified new shape of an expansion chamber and nozzle has been suggested to improve the efficiency of gas flow and to provide guidelines for designing self-blast breaker with a higher interruption capability.

Numerical Analysis on Characteristics of Blast Wave in Open Space and Structure (개활지 및 구조물 내에서의 폭풍파 특성에 대한 수치 분석)

  • Roh, Taejun;Lee, Younghun;Ji, Juntae;Lee, Woonghyun;Yoh, Jai-ick
    • Journal of the Korea Institute of Military Science and Technology
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    • v.23 no.1
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    • pp.43-51
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    • 2020
  • In this study, numerical analysis was carried out on a complex pressure field of blast waves caused by the detonation of high explosives in various environments. The generated blast waves propagated in the air, upon the sudden release of high energy induced by the explosion. Reflected waves were created when the pressure waves encountered certain obstacles such as the ground or the walls of structures. The propagation of the blast waves and its interaction with the reflected waves were simulated. An adaptive mesh refinement was applied to improve the efficiency of distribution of computer resource, for the computational calculation of the blast wave propagation in a wide open space. In addition, the integration of the calculation domains for the explosive and air were considered when the maximum density of the explosive region was below critical value. The results were verified by comparison with the pressure time history from blast wave experiments performed under two topographical conditions.

Optimum Delay Time of Electronic Detonator using Blast-induced Vibration Waveform Composition (발파진동 파형합성을 이용한 전자뇌관의 최적지연초시에 관한 연구)

  • Yoon, Ji-sun;Kim, Do-hyun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.8 no.2
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    • pp.129-139
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    • 2006
  • When blasting by imposing the time difference between two adjacent charge holes, the mutual interference phenomenon occurs depending the feature of blast. This interference phenomenon of blast amplifies or compensates the blast-induced vibration depending on the overlapping mechanism. Thus, this experiment aims at finding out the optimum delay time by measuring the blast vibration data from the single hole blast during the blasting test and composing each blasting waveform, and at proving the its efficiency by applying the composition delay time in the entire cross section. The experiment showed that the blasting-induced vibration was reduced by endowing an optimum delay time of electronic detonator appropriate to the rock quality of construction site compared to the typical delay time (20, 25ms) of existing detonator (non-electric and electric detonator). From these results, the excavation efficiency using blasting could be enhanced..

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Analysis of Furnace Conditions with Waste Plastics Injection into Blast Furnace (폐플라스틱의 吹入에 따른 高爐 爐況解析)

  • 허남환;백찬영;임창희
    • Resources Recycling
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    • v.9 no.6
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    • pp.23-30
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    • 2000
  • Since most of the waste plastics are incinerated and landfilled for the plastic treatment, the environmental friendly processes must be introduced. The plastic utilization of plastic to the blast furnace as a substitutional fuel was developed as a useful recycling method of waste plastics, and commercialized in several ironmaking company in Europe and Japan. Present study was carried out to understand the effect of plastic injection on blast furnace process continuously by using the foundry blast furnace in POSCO. The coke replacement ratio turned out to be 0.98 with the waste plastic injection up to 13.8 kg/thm of injection rate, and there were no significant effect of the kinds of injection plastics on the replacement ratio in this test operation. The permeability in the furnace became worse and the heat load in the lower part of blast furnace was increased with increasing the injection rate of waste plastics. As the rate of plastic injection were increased, the top gas utilization and shaft efficiency were also decreased from the Rist diagram analysis.

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An Experimental Study on the Fluidity and Engineering Properties of Concrete Using Ground Granulated Blast-Furnace Slag (고로슬래그미분말을 대량 활용한 콘크리트의 유동성 및 공학적 특성에 관한 실험적 연구)

  • Cho, Bong-Suk;Nam, Jeong-Soo;Lee, Eui-Bae;Back, Yong-Kwan;Kim, Gyu-Yong;Kim, Moo-Han
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05b
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    • pp.473-476
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    • 2006
  • As a part of efforts to obtain high quality and economical efficiency of concrete, blast-furnace slag has been utilized by means of cement replacement. Therefore superior performance can be ensured, environmental pollution can be prevented and economical advantage can be obtained with utilization by cement replacement. But the studies on the blast-furnace slag are not systematic and reasonable. So, it was planed that basic data in regard to technique of manufacturing and economic improvement of concrete is showed with experimental comparison and investigation of Fluidity and engineering properties of concrete utilizing blast-furnace, industry by-product, as cement replacement in this study.

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Joint OSIC and Soft ML Decoding Scheme for Coded Layered Space-Time OFDM Systems

  • Lee, Hye-Jeong;Chung, Jae-Ho;Park, Se-Jun;Lee, Seong-Choon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.5A
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    • pp.487-493
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    • 2008
  • In this paper, we consider coded layered space-time architecture in MIMO-OFDM channels. Vertical Bell Lab Layered Space-Time(V-BLAST) scheme employing ordered successive interference cancellation(OSIC) algorithm provides very high spectral efficiency with low computational complexity. However, the error propagation is a major drawback constraining the overall performance of the V-BLAST system significantly. Based on this problem, we derive an improved detector using soft bit log-likelihood ratio(LLR) value. Simulation results show that the proposed detector outperforms the conventional V-BLAST scheme under spatially uncorrelated as well as correlated fading channels.

Liuux Cluster based Biological Sequence Parallel Processing Model Development and Efficiency Verification (리눅스 클러스터기반 유전자서열분석 병렬처리 모형 개발 및 성능 검증)

  • 박미화;김재우;박춘규;유승식
    • Proceedings of the Korean Information Science Society Conference
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    • 2003.04a
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    • pp.106-108
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    • 2003
  • Human Genome Project와 같은 대형 Sequencing 프로젝트와 High-throughput Sequencing 기술의 발전으로 현재 Expressed Sequence Tag (EST)와 같은 대량의 DNA 서열들이 생산되고 있다. 이를 효과적이고 효율적으로 분석해야 할 필요성이 증대되고 있다. 대부분의 실험자들이 서열 분석을 위해 우선적으로 BLAST 검색을 이용하고 있다. 하지만 대량의 서열, 검색 DB의 크기, BLAST 검색 결과의 복잡성에 의해 어려움을 겪고 있다. 이에 빠르고 정리된 결과를 보여줄 수 있는 BLAST 검색 시스템의 필요성이 커지고 있다. 이에 본 논문은 미국 생명공학연구소(NCBI)에서 제공하는 유전자 서열 검색 툴인 BLAST(Basic Logical Alignment Tool)를 클러스터 수퍼 컴퓨터 구축 기술을 기반으로 한 병렬처리와 Gene Ontology를 이용하여 방대한 양의 서열 검색 결과를 요약하는 모형을 제시한다. 이것은 신약개발 및 유전자 발굴 등의 연구기간을 획기적으로 단축시켜 신약 개 발, 농업, 화학, 의료, 환경 등 생명공학 연구에 핵심적인 역할을 할 수 있다. 또한 성능 실험을 통하여 분석결과 대기시간을 최소화하는 병렬처리모형의 효율성을 검증하였다.

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Estimation of Characteristics Treatment for Food Waste with Blast Volume and Preheating of Air using Bio-Drying Process (Bio-drying 공법 활용 공기 투입 및 예열에 따른 음식물류 폐기물 분해 특성 평가)

  • Park, Seyong;Lee, Wonbea
    • Journal of the Korea Organic Resources Recycling Association
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    • v.30 no.4
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    • pp.15-25
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    • 2022
  • In this study, the efficiency of treatment of moisture and organic matter in food waste was analyzed according to the air blast volume and preheating using the bio-drying method. Te mount of air blast volume and preheating were determined by the evaluation of temperature and CO2 during food waste treatment using the bio-drying method. As a results, the increase in the air blast volume increased the moisture removal efficiency and removal rate, but, lowered the temperature inside the bio-drying by the decease in microbial activity. In order to maintain the activity of microorganisms, it was estimated that it was necessary to inject an appropriate air blast rate according th the properties of the food waste. In this study, the injection of air blast volume at 15L/min was optimal. It was evaluated that the organic matter and water removal rates according to the presence or absence of air preheating, the organic matter removal rate and water removal rate increased by 3-5% when air preheating was not performed. Also, there was no internal aggregation caused by the generation of condensate inside the bio-drying. Therefore, for effective bio-drying of food waste, it is necessary to maintain an appropriate air blast volume to maintain microbial activity, and it is considered that injection through preheating of air is required.

Alteration of Gas Exchange in Rice Leaves Infected with Magnaporthe grisea

  • Yun, Sung-Chul;Kim, Pan-Gi;Park, Eun-Woo
    • The Plant Pathology Journal
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    • v.16 no.5
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    • pp.257-263
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    • 2000
  • Infection with rice blast fungus (Magnaporthe grisea) significantly reduced foliar net photosynthesis (A) of rice cultivars: Ilpoom, Hwasung, and Choochung in greenhouse experiments. By measuring the amount of diseased leaf area with a computer image analysis system, the relation between disease severity (DS) and net photosynthetic rate was curvilinearly correlated (r=0.679). Diseased leaves with 35% blast symptom can be predicted to have a 50% reduction of photosynthesis. The disease severity was linearly correlated (r=0.478) with total chlorophyll (chlorophyll a and chlorophyll b) per unit leaf area(TC). Light use efficiency was reduced by the fungal infection according to the light response curves. However, dark respiration (Rd) did not change after the fungal infection (p=0.526). Since the percent of reduction in photosynthesis greatly exceeded the percent of leaf area covered by blast lesions, loss of photosynthetic tissue on an area basis could not by itself account for the reduced photosynthesis. Quantitative photosynthetic reduction can be partially explained by decreasing TC, but cannot be explained by decreasing Rd. By photosynthesis (A)-internal CO$_2$ concentration (C$_i$ curve analysis, it was suggested that the fungal infection reduced ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity, ribulose-1,5-bisphosphate (RuBP) regeneration, and inorganic phosphate regeneration. Thus, the reduction of photosynthesis by blast infection was associated with decreased TC and biochemical capacity, which comprises all carbon metabolism after CO$_2$ enters through the stomata.

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