• Title/Summary/Keyword: Flow control system

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Phase Separation Characteristics via Bunsen Reaction in Sulfur-Iodine Thermochemical Hydrogen Production Process (SI 열화학 수소 제조 공정에서 분젠 반응을 통한 상 분리 특성)

  • Lee, Kwang-Jin;Kim, Young-Ho;Park, Chu-Sik;Bae, Ki-Kwang
    • Journal of Hydrogen and New Energy
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    • v.19 no.5
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    • pp.386-393
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    • 2008
  • The Sulfur-iodine(SI) thermochemical cycle is one of the most promising methods for massive hydrogen production. For the purpose of continuous operation of SI cycle, phase separation characteristics into two liquid phases ($H_2SO_4$-rich phase and $HI_x$-rich phase) were directly investigated via Bunsen reaction. The experiments for Bunsen reaction were carried out in the temperature range, from 298 to 333 K, and in the $I_2/H_2O$ molar ratio of $0.109{\sim}0.297$ under a continuous flow of $SO_2$ gas. As the results, solubility of $SO_2$, decreased with increasing the temperature, had considerable influence on the global composition in the Bunsen reaction system. The amounts of impurity in each phase(HI and $I_2$ in $H_2SO_4$-rich phase and $H_2SO_4$ in $HI_x$-rich phase) were decreased with increasing $H_2SO_4$ molar ratio and temperature. To control the amounts of impurity in $HI_x$-rich phase, temperature is a factor more important than $I_2/H2_O$ molar ratio. On the other hand, the affinity between $HI_x$ and $H_2O$ was increased with increasing $I_2/H2_O$molar ratio.

Solubility Consideration in Performance Analysis of a $CO_2$ Twin Rotary Compressor (오일 용해도를 고려한 $CO_2$ 트윈 로타리 압축기 성능해석)

  • Kim, Woo-Young;Ahn, Jong-Min;Kim, Hyun-Jin;Cho, Sung-Oug
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.12
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    • pp.842-849
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    • 2007
  • For a $CO_2$ two-stage twin rotary compressor used for heat pump water heater system, changes of $CO_2$ solubility in PAG oil were investigated along the gas passages from the first stage suction to final discharge. Only slight changes in solubility took place in suction chambers for both of the first and second stages, but for compression chambers, solubility variation ranged from 0.115 to 0.136, and from 0.133 to 0.182, respectively for the first and second stages. Calculation of gas flashing in parts of leakage oil flows and of oil contained in control volumes due to solubility changes was conducted and included in gas pressure calculation. For the second stage, gas flashing amounts to around $5%\sim6%$ for most leakage flows. Cooling capacity, compressor input, and COP obtained by calculation were well compared to the experimental results. Effects of operation speed on the compressor performance was also studied: as the shaft speed increased, adiabatic efficiency decreased rapidly due to increased over-compression loss.

A study on the Healing Mechanism of Herbal Medicine, Oryoungsan (오령산의 작용기전(作用機轉)에 대한 고찰(考察))

  • Nam, Hyoung-sin;Cho, Chung-sik;Kim, Chul-jung
    • Journal of Haehwa Medicine
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    • v.10 no.1
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    • pp.157-166
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    • 2001
  • Oryoungsan which first recorded in Sanghanron, the clinical medical book consists of treating acute febrile disease according to its change, is one of the frequently used oriental medicines. these days, it has been prescribed in symptoms accompanied by edema mostly. therefore it is easy to consider it as a type of diuretics. In Sanghanron it was originally used in the symptoms of perspiration, decreased urine volume, thirsty, flatulence. these symptoms indicate loss of body fluid and the prescription which orders "taking warm water sufficiently" supports this. On this background, it is supposed that Oryoungsan treats dehydration after providing water and electrolytes. To consider that herbal medicines consisted of Oryoungsan make electrolytes go out of the body, The healing mechanism of dehydration doesn't meet this. Because Oryoungsan was used in condition of fever or in similar condition, it is more resonable to understand that restoration of increasing blood flow to the subcutaneous venous plexus regulating body temperature in febrile condition into body circulation, resulting into maintaining main blood volume and into treating decreased urine volume and thirsty is Oryoungsan's function in the dehydration or febrile condition. That is, symptoms are decreased or disappeared through restoring unbalance of internal body fluid. The other target is pain controls, especially chronic headache, facial pain and trigeminal neuralgia. it is suggested that the function of pain control of Oryoungsan is related to 5-HT(5-hydroxytrypamine), nerve transmitter in the endogenous analgesic system. Moreover it is also suggested that Oryoungsan is relate to 5-HT, considering the fact that gastroparesis, a symptom of cyclic vomiting syndrome treated with 5-HT1D receptor agonist is similar to the 'bi', symptoms appeared in the Oryoungsan-related disease.

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Optimization of Detention Facilities by Using Multi-Objective Genetic Algorithms (다목적 유전자 알고리즘을 이용한 우수유출 저류지 최적화 방안)

  • Chung, Jae-Hak;Han, Kun-Yeun;Kim, Keuk-Soo
    • Journal of Korea Water Resources Association
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    • v.41 no.12
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    • pp.1211-1218
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    • 2008
  • This study is for design of the detention system distributed in a watershed by the Multi-Objective Genetic Algorithms(MOGAs). A new model is developed to determine optimal size and location of detention. The developed model has two primary interfaced components such as a rainfall runoff model to simulate water surface elevation(or flowrate) and MOGAs to get the optimal solution. The objective functions used in this model depend on the peak flow and storage of detention. With various constraints such as structural limitations, capacities of storage and operational targets. The developed model is applied at Gwanyang basin within Anyang watershed. The simulation results show the maximum outlet reduction is occurred at detention facilities located in upper reach of watershed in the peak discharge rates. It is also reviewed the simultaneous construction of an off-line detention and an on-line detention. The methodologies obtained from this study will be used to control the flood discharges and to reduce flood damage in urbanized watershed.

A Case Report of Hypoxic Ischemic Encephalopathy followed by Cardiopulmonary Resuscitation (심폐소생술후 발생한 저산소성 허혈성 뇌손상 환아(患兒) 치험 1례(例))

  • You, Han-Jung;Cho, Baek-Gun;Lee, Jin-Yong;Kim, Deog-Gon;Koh, Duck-Jae
    • The Journal of Pediatrics of Korean Medicine
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    • v.19 no.2
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    • pp.255-269
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    • 2005
  • Objective : To evaluate the effect of Oriental Medical Treatment on a patient with Hypoxic Ischemic Encephalopathy followed by Cardiopulmonary Resuscitation Method : We applied various methodology of Oriental Medical Treatment including Acupuncture, Electroacupuncture, Physical treatment, Herbal Medicine, Moxibustion treatment and Western medication as well. Result: Herbal medicine was applied on the basis of the patient's history. We applied formular to remove phelgm as a pathogenic factor after Hypoxic Ischemic Encephalopathy. At the same time, considering the patient spent more than a month in ICU lacking appropriate nutrition, we used formuli on the basis of 'Deficiency of Spleen' focusing to vitalize the function of digestive system. As the condition of the patient changed, we also adapted formular accordingly. We prescribed Herbal medication to strengthen Yin and Yang equally as she got hospitalized for long time. Also we applied Acupuncture treatment and Moxibustion treatment to control Qi flow. The general condition of the patient got better with successful removal of Foley catheter and elevated Glasgow Coma scale. We used Electroacupuncture, Physical treatment and Western medication at the same to get maximized effect on relaxing the contracted muscle. According to the Modified Ashworth Scale (MAS), we have some changes in muscle spasticity but later, the effect was not that significant. Conclusion : We had a patient with Hypoxic Ischemic Encephalopathy followed by Cardiopulmonary Resuscitation. In the management of Hypoxic Ischemic Encephalopathy, Conservative treatments are the mainstream but there are not many alternatives. Therefore, We suggest that Oriental medical approach may contribute to the management of Hypoxic Ischemic Encephalopathy.

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The design of outlet in inter-cross slope with tunnel which it applied forming artificial ground (인공지반을 적용한 사교하는 사면에서의 터널 갱구부 설계)

  • Park, Chal-Sook;Kwan, Han;Lee, Kyu-Tak;Kim, Bong-Jae;Yun, Yong-Jin;Kim, Kwang-Hee
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1532-1548
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    • 2008
  • The tunnel type spillways is under construction to increasing water reservoir capacity in Dae-am dam. The tunnel outlet was planned to be made after installing slope stabilization system on natural slope there. Generally, the tunnel outlet is made perpendicularly to the slope, but in this case, it had to be made obliquely to the slope for not interrupting flow of river. Because of excavation in condition of natural slope caused to deflecting earth pressure, the outlet couldn't be made. So, artificial ground made with concrete that it was constructed in the outside of tunnel for producing the arching effect which enables to make a outlet. We were planned tunnel excavation was carried out after artificial ground made. Artificial ground made by poor mix concrete of which it was planned that the thickness was at least 3.0m height from outside of tunnel lining and 30cm of height per pouring. Spreading and compaction was planned utilized weight of 15 ton roller machine. In order to access of working truck, slope of artificial ground was designed 1:1.0 and applied 2% slope in upper pert of it for easily drainage of water. In addition to, upper pert of artificial ground was covered with soil, because of impaction of rock fall from upper slope was made minimum. The tunnel excavation of the artificial ground was designed application with special blasting method that it was Super Wedge and control blasting utilized with pre-percussion hole.

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Evaluation of wireless communication devices for remote monitoring of protected crop production environment (시설재배지 환경 원격 모니터링을 위한 무선 통신 장비 평가)

  • Hur, Seung-Oh;Ryu, Myong-Jin;Ryu, Dong-Ki;Chung, Sun-Ok;Huh, Yun-Kun;Choi, Jin-Yong
    • Korean Journal of Agricultural Science
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    • v.38 no.4
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    • pp.747-752
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    • 2011
  • Wireless technology has enabled farmers monitor and control protected production environment more efficiently. Utilization of USN (Ubiquitous Sensor Network) devices also brought benefits due to reduced wiring and central data handling requirements. However, wireless communication loses signal under unfavorable conditions (e.g., blocked signal path, low signal intensity). In this paper, performance of commercial wireless communication devices were evaluated for application to protected crop production. Two different models of wireless communication devices were tested. Sensors used in the study were weather units installed outside and top of a greenhouse (wind velocity and direction, precipitation, temperature and humidity), inside ambient condition units (temperature, humidity, $CO_2$, and light intensity), and irrigation status units (irrigation flow and pressure, and soil water content). Performance of wireless communication was evaluated with and without crop. For a 2.4 GHz device, communication distance was decreased by about 10% when crops were present between the transmitting and receiving antennas installed on the ground, and the best performance was obtained when the antennas were installed 2 m above the crop canopy. When tested in a greenhouse, center of a greenhouse was chosen as the location of receiving antenna. The results would provide information useful for implementation of wireless environment monitoring system for protected crop production using USN devices.

A Study on Farmer's Requisition on Welfare Policy (농업인 복지정책 요구도 분석)

  • Ryoo Hak Soo;Cho Young Sook
    • The Korean Journal of Community Living Science
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    • v.16 no.2
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    • pp.51-59
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    • 2005
  • The purpose of the present study is to seek measures to increase the quality of farmers lives by considering the results of a survey on the welfare demand for them when setting up policy. The results are as follows: First, though many concerns and policies to control the rural exodus have been exerted in terms of maintaining agricultural communities, which is one of critical components for the development of Korean agriculture and farming villages, the rural exodus became more and more serious. It is urgently required, therefore, for the Korean administration to correspond actively to the reasons why farmers depart their villages, such as bad prospects, low incomes or problems with their children's education. Second, as the number of females who take part in farming has increased, it is necessary to reform the rural educational environment. In addition, as the agricultural community develops, and other industries flow in, the greater the worries about crime, and consequently, it is necessary to equip a local safety system, share information on job opportunities, and provide educational opportunities. Third, since rural districts nay have financial difficulties because of old-aged and small-sized farmhouse, it is necessary to mainly support the welfare of the aged and lower-income farmers, considering the characteristics of each group and area. Fourth, over half of the farmers responded that they cannot bear to pay the national pension and health insurance premiums, and therefore it should be considered to reduce the pension and premium, or to readjust the insurance value appropriate to the level of the farmer's income. Fifth, despite a number of agricultural policies now in place, farmers desire a policy which can promise a prosperous vision for Korean agriculture and the facilities needed for education and health. It is necessary for the administration to set up policies that are characterized by locality with the view that farmers are not mere recipients, but participants in the policies.

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Construction Method of Time-dependent Origin-Destination Traffic Flow for Expressway Corridor Using Individual Real Trip Data (실제 통행기록 자료를 활용한 고속도로 Corridor 시간대별 O-D 구축)

  • Yu, Jeong Whon;Lee, Mu Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.2D
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    • pp.185-192
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    • 2011
  • More practical outputs and insights can be obtained through transportation analysis considering the time-dependent traffic movements. This study proposes a method of constructing time-dependent O-D trip tables for expressway corridor using real-world individual trip data. In this study, time-dependent O-D trip tables for the nationwide highway network are constructed based on toll collection system data. The proposed methodology is to convert nationwide time-dependent O-D trip tables into Korean expressway corridor O-D trip tables in order to deal with the computational complexity arising from simulating a large-scale traffic network. The experiment results suggest that actual individual trip record data can be used to effectively construct time-dependent O-D trip tables. They also imply that the construction of time-dependent O-D trip tables for the national highway networks along with those for Korean expressway developed in this study would make transportation analysis more practical and applicable to real-time traffic operation and control.

Cross-Layer Optimized Resource Allocation Scheme for OFDMA based Micro Base Stations (OFDMA 기반 마이크로 기지국을 위한 계층간 최적화된 자원할당 기법)

  • Cho, Sung-Hyun
    • Journal of the Korea Society of Computer and Information
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    • v.15 no.6
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    • pp.49-56
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    • 2010
  • In this paper, a joint PHY-MAC layer optimized resource allocation scheme for OFDMA based micro base stations is investigated. We propose cross-layer optimized two-stage resource allocation scheme including cross-layer functional description and control information flow between PHY-MAC layers. The proposed two-stage resource allocation scheme consists of a user grouping stage and a resource allocation stage. In the user grouping stage, users are divided into a macro base station user group and a micro base station user group based on the PHY-MAC layer characteristics of each user. In the resource allocation stage, a scheduling scheme and an allotment of resources are determined. In the proposed scheme, diversity and adaptive modulation and coding (AMC) schemes are exploited as schedulers. Simulation results demonstrate that the proposed scheme increases the average cell throughput about 40~80 % compared to the conventional system without micro base stations.