• Title/Summary/Keyword: carbon number distribution

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Microstructure Characteristics of Conductive Cement Mortar with Deterioration Damage (열화손상이 발생된 전도성시멘트모르타르의 미세구조 특성)

  • Kim, Young-Min;Lee, Gun Cheol;Yun, Hyun Do;Kwon, Hyun Woo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.05a
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    • pp.195-196
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    • 2021
  • The pore distribution of the cement mortar mixed with carbon nanotubes was found to have a large number of pores at (370~80)㎛, and the distribution ratio was larger as the carbon nanotubes were mixed. However, the pores with a fine particle diameter of (10-0.5) ㎛ were found to be larger as the carbon nanotubes were incorporated. However, the distribution of pores of the test specimens of conductive cement mortar with deterioration damage was found to be distributed in a number of particle diameters of (500 to 100) ㎛ and (10 to 0.5) ㎛. It is judged that the particle diameter of the internal pores increased due to the damage. However, as the mixing ratio of the test specimen with carbon nanotubes increased, the distribution of voids was relatively lower than that of plain, and it was judged to have excellent resistance to deterioration damage.

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Modeling of Thermal Conductivity of Carbon Spun Yarn (탄소 방적사의 열전도도 모델링)

  • Cho Young Jun;Sul In Hwan;Kang Tae Jin;Park Jong Kyoo
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.04a
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    • pp.186-189
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    • 2004
  • A thermal model of carbon spun yam is presented. The unit cell of spun carbon yam is divided into a number of volume elements and the local material properties have been given to each element. By using Finite Difference Method (FDM), temperature distribution in the unit cell can be obtained. Effective thermal conductivity of the spun carbon yam unit cell is calculated using the temperature distribution and thermal conductivities of local elements.

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A Stochastic Study for the Emergency Treatment of Carbon Monoxide Poisoning in Korea (일산화탄소중독(一酸化炭素中毒)의 진료대책(診療對策) 수립(樹立)을 위한 추계학적(推計學的) 연구(硏究))

  • Kim, Yong-Ik;Yun, Dork-Ro;Shin, Young-Soo
    • Journal of Preventive Medicine and Public Health
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    • v.16 no.1
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    • pp.135-152
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    • 1983
  • Emergency medical service is an important part of the health care delivery system, and the optimal allocation of resources and their efficient utilization are essentially demanded. Since these conditions are the prerequisite to prompt treatment which, in turn, will be crucial for life saving and in reducing the undesirable sequelae of the event. This study, taking the hyperbaric chamber for carbon monoxide poisoning as an example, is to develop a stochastic approach for solving the problems of optimal allocation of such emergency medical facility in Korea. The hyperbaric chamber, in Korea, is used almost exclusively for the treatment of acute carbon monoxide poisoning, most of which occur at home, since the coal briquette is used as domestic fuel by 69.6 per cent of the Korean population. The annual incidence rate of the comatous and fatal carbon monoxide poisoning is estimated at 45.5 per 10,000 of coal briquette-using population. It offers a serious public health problem and occupies a large portion of the emergency outpatients, especially in the winter season. The requirement of hyperbaric chambers can be calculated by setting the level of the annual queueing rate, which is here defined as the proportion of the annual number of the queued patients among the annual number of the total patients. The rate is determined by the size of the coal briquette-using population which generate a certain number of carbon monoxide poisoning patients in terms of the annual incidence rate, and the number of hyperbaric chambers per hospital to which the patients are sent, assuming that there is no referral of the patients among hospitals. The queueing occurs due to the conflicting events of the 'arrival' of the patients and the 'service' of the hyperbaric chambers. Here, we can assume that the length of the service time of hyperbaric chambers is fixed at sixty minutes, and the service discipline is based on 'first come, first served'. The arrival pattern of the carbon monoxide poisoning is relatively unique, because it usually occurs while the people are in bed. Diurnal variation of the carbon monoxide poisoning can hardly be formulated mathematically, so empirical cumulative distribution of the probability of the hourly arrival of the patients was used for Monte Carlo simulation to calculate the probability of queueing by the number of the patients per day, for the cases of one, two or three hyperbaric chambers assumed to be available per hospital. Incidence of the carbon monoxide poisoning also has strong seasonal variation, because of the four distinctive seasons in Korea. So the number of the patients per day could not be assumed to be distributed according to the Poisson distribution. Testing the fitness of various distributions of rare event, it turned out to be that the daily distribution of the carbon monoxide poisoning fits well to the Polya-Eggenberger distribution. With this model, we could forecast the number of the poisonings per day by the size of the coal-briquette using population. By combining the probability of queueing by the number of patients per day, and the probability of the number of patients per day in a year, we can estimate the number of the queued patients and the number of the patients in a year by the number of hyperbaric chamber per hospital and by the size of coal briquette-using population. Setting 5 per cent as the annual queueing rate, the required number of hyperbaric chambers was calculated for each province and for the whole country, in the cases of 25, 50, 75 and 100 per cent of the treatment rate which stand for the rate of the patients treated by hyperbaric chamber among the patients who are to be treated. Findings of the study were as follows. 1. Probability of the number of patients per day follows Polya-Eggenberger distribution. $$P(X=\gamma)=\frac{\Pi\limits_{k=1}^\gamma[m+(K-1)\times10.86]}{\gamma!}\times11.86^{-{(\frac{m}{10.86}+\gamma)}}$$ when$${\gamma}=1,2,...,n$$$$P(X=0)=11.86^{-(m/10.86)}$$ when $${\gamma}=0$$ Hourly arrival pattern of the patients turned out to be bimodal, the large peak was observed in $7 : 00{\sim}8 : 00$ a.m., and the small peak in $11 : 00{\sim}12 : 00$ p.m. 2. In the cases of only one or two hyperbaric chambers installed per hospital, the annual queueing rate will be at the level of more than 5 per cent. Only in case of three chambers, however, the rate will reach 5 per cent when the average number of the patients per day is 0.481. 3. According to the results above, a hospital equipped with three hyperbaric chambers will be able to serve 166,485, 83,242, 55,495 and 41,620 of population, when the treatmet rate are 25, 50, 75 and 100 per cent. 4. The required number of hyperbaric chambers are estimated at 483, 963, 1,441 and 1,923 when the treatment rate are taken as 25, 50, 75 and 100 per cent. Therefore, the shortage are respectively turned out to be 312, 791. 1,270 and 1,752. The author believes that the methodology developed in this study will also be applicable to the problems of resource allocation for the other kinds of the emergency medical facilities.

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A Study on Relationship between Fuel Characteristics and Combustion Characteristics of Reformed Diesel Fuels by Ultrasonic Energy Irradiation (II) - Relationship between Chemical Structure and Cetane Number - (초음파 개질 경유의 연료특성과 연소특성의 상관관계에 관한 연구 (II) -화학구조와 세탄가의 상관성-)

  • 이병오;류정인
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.1
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    • pp.64-71
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    • 2003
  • In order to analyze the effect of the chemical structure and the cetane number of reformed diesel fuels by ultrasonic energy irradiation, proton nuclear magnetic resonance spectrometer$(^1H-NMR)$ was used. From the study, following conclusive remarks can be made. 1) Branch Index(BI), aromatics percentages, and alpha methyl radical$(H_{\alpha})$ of the reformed diesel fuels by ultrasonic energy irradiation decreased more than the conventional ones. 2) All the cetane numbers which were calculated from carbon type structure and hydrogen type distribution of the reformed diesel fuels increased more than the conventional ones. 3) It is more reasonable to predict cetane number equation from carbon type structure than from hydrogen type distribution. 4) BI, aromatics percentages, and $H_{\alpha}$ on both for conventional fuel and reformed diesel fuels by ultrasonic energy irradiation are inversely proportional to cetane number fur these fuels.

Transient vibration analysis of FG-MWCNT reinforced composite plate resting on foundation

  • Kumar, Puneet;Srinivas, J.
    • Steel and Composite Structures
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    • v.29 no.5
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    • pp.569-578
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    • 2018
  • This paper aims to investigate the transient vibration behavior of functionally graded carbon nanotube (FG-CNT) reinforced nanocomposite plate resting on Pasternak foundation under pulse excitation. The plate is considered to be composed of matrix material and multi-walled carbon nanotubes (MWCNTs) with distribution as per the functional grading concept. The functionally graded distribution patterns in nanocomposite plate are explained more appropriately with the layer-wise variation of carbon nanotubes weight fraction in the thickness coordinate. The layers are stacked up in such a way that it yields uniform and three other types of distribution patterns. The effective material properties of each layer in nanocomposite plate are obtained by modified Halpin-Tsai model and rule of mixtures. The governing equations of an illustrative case of simply-supported nanocomposite plate resting on the Pasternak foundation are derived from third order shear deformation theory and Navier's solution technique. A converge transient response of nanocompiste plate under uniformly distributed load with triangular pulse is obtained by varying number of layer in thickness direction. The validity and accuracy of the present model is also checked by comparing the results with those available in literature for isotropic case. Then, numerical examples are presented to highlight the effects of distribution patterns, foundation stiffness, carbon nanotube parameters and plate aspect ratio on the central deflection response. The results are extended with the consideration of proportional damping in the system and found that nanocomposite plate with distribution III have minimum settling time as compared to the other distributions.

Fatique Analysis of RC Beams Strengthened by Steel Plate or Carbon Fiber Sheet (강판 및 탄소섬유 sheet로 보강된 철근콘크리트 보의 피로해석)

  • Sim, Jong-Sung;Hwang, Eui-Seung;Bae, In-Hwan;Jang, Sang-Hoon
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.10a
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    • pp.703-708
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    • 1997
  • In this study, the fatigue tests are performed on simply-supported R/C beams strengthened with steel plate and CFS (Carbon fiber sheet). Analysis results by Weibull distribution are compared with the test data. The unknown Weibull distribution parameters are estimated based on observations recorded in fatigue test. Safety factors for the number of cycles and the stress level are obtained. S-N-P curves are also generated from these testes and probabilities of failure.

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Three-Dimensional Fluid Flow Analysis of Automotive Carbon Canister for Reducing Evaporative Emissions (증발가스 배출물 억제를 위한 자동차용 캐니스터의 3차원 유동장 해석)

  • 정수진;김우승
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.6
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    • pp.85-93
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    • 2001
  • Minimized canister flow restriction and maximized flow uniformity are desired to maximize a purge capability. With the impending ORVR(On Board Refueling Vapor Recovery) systems, the reduction of restriction and increase of flow uniformity in a carbon canister becomes even more critical to meet the stringent regulation. In this study, three-dimensional numerical simulations have been performed to investigate the three-dimensional internal flow patterns in a carbon canister during purge. The effects of the declined angle of the purge pipe and the number of partitions on the pressure drop and purge efficiency in a carbon packed bed are examined. Results show that the purge efficiency and space velocity distribution are affected in the upstream region of 40% of total canister bed by porosity of carbon granule and angle of purge pipe. It is also found that the purge efficiency decreases with increasing the number of partitions.

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A Study on Correlation of Fuel Characteristics and Combustion Characteristics of Reformed Diesel Fuels by Ultrasonic Irradiation (II);Correlation of Chemical Structure and Cetane Number (초음파 개질 경유의 연료특성과 연소특성의 상관성에 관한 연구 (II);화학구조와 세탄가의 상관관계)

  • Lee, Byoung-Oh;Kim, Yong-Kuk;Kwon, Oh-Sung;Choi, Doo-Seuk;Ryu, Jeong-In
    • 한국연소학회:학술대회논문집
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    • 2002.06a
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    • pp.163-170
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    • 2002
  • The main objective of this study is to investigate the correlation of chemical structure and cetane number of reformed diesel fuels by ultrasonic irradiation. In order to analyze the effect of the chemical structure and the cetane number of reformed diesel fuels by ultrasonic irradiation, $^1H-NMR$ was used. From the study, following conclusive remarks can be made. 1) BI(=Branch Index), aromatics percentages, and $H_{\alpha}(={\alpha}-methyl$ functional group) of the reformed diesel fuels by ultrasonic irradiation decreased more than those of the conventional diesel fuel. 2) All the cetane numbers which were calculated from carbon type structure and hydrogen type distribution of the reformed diesel fuels increased more than those of the conventional diesel fuel. 3) Using predicated equation of cetane number caculated from carbon type structure is more reasonable than that caculated from hydrogen type distribution 4) BI, aromatics percentages, and $H_{\alpha}$ on both of conventional fuel and reformed diesel fuels by ultrasonic irradiation are inversely proportional to cetane number on these fuels.

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Probabilistic Analysis on the Fatigue-Life of the Strengthened Bridge Decks (성능향상된 교량 바닥판에서의 피로수명에 대한 확률론적 해석)

  • 심종성;오홍섭;류승무;박성재
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.393-398
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    • 2002
  • This study shows the fatigue test results of experiment on the strengthened slabs, the probability analysis of the fatigue behavior is also presented. Static und fatigue tests were performed on bridge decks strengthened with fiber plastics(Carbon Fiber Sheet, Glass Fiber Sheet, Grid Type Carbon Fiber). In this study, to analyze the probabilistic distribution of the fatigue life, the Weibull distribution was adopted. The Weibull distribution coefficient is inferred from the S-N diagram and the number of repeated load. As the result analysis, as the stress level is higher, the fatigue limit of the strengthened bridge deck are similarly discovered but in the range of the fatigue limit, CG specimen that was strengthened with Grid Type Carbon was proved most effective of reinforcement.

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Voxelization-based Model for Predicting Thermal Conductivities of Spun Type Carbon Fabric Composites (복셀화기법을 이용한 탄소방적사강화 복합재료의 열전도도 모델링)

  • Cho, Young-Jun;Sul, In-Hwan;Kang, Tae-Jin;Park, Jong-Kyoo
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.04a
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    • pp.90-93
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    • 2005
  • A thermal model of carbon spun yarn and its composite is presented. Based on voxelization method, the unit cells of spun carbon yam and its composite are divided into a number of volume elements and the local material properties have been given to each element. By using Finite Difference Method, temperature distribution in the unit cell can be obtained. Effective thermal conductivity of unit cell is calculated using the temperature distribution and thermal conductivities of local elements.

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