• Title/Summary/Keyword: PM10 Flow

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Evaluation of Critical Flow Factor in Natural Gas Flow Measurement Using Sonic Nozzle and International Comparison Results (소닉노즐을 이용한 천연가스 유량측정에서 임계유동인자 계산 및 국제비교 결과)

  • Ha, Youngcheol;Her, Jaeyoung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.7
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    • pp.911-917
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    • 1999
  • The sonic nozzle is widely used as reference device for calibrating flowmeters In gas flow measurement and its use requires the Critical Flow Factor(CFF) based on the thermodynamic properties of the gas at the nozzle throat. ISO-9300 provides the calculating method of the factor. But since the CFF from this method show an error over ${\pm}0.5%$ In specific conditions and of ${\pm}0.1{\sim}{\pm}0.2%$ in common Natural Gas(NG) custody transfer condition. this method cannot be applied for gas flow measurement with sonic nozzle. Each research bodies or organizations of the world have joined in order to calculate the CFF more accurately. They have performed these works using their own method and compared the results with each other under the management of ISO. KOGAS have joined those works, because the high-pressure natural gas flow calibration facility of KOGAS will be constructed in late 1999, and then had necessities to calculate a CFF accurately. The calculation method of KOGAS was using the equation of state from AGA-8('94), high accuracy model of ideal gas properties and the solutions of thermodynamic equations. The evaluation results have had a very good consistency within ${\pm}0.05%$ in most NO custody transfer conditions compared to the speed of sound for methane and also shown that the CFF was within ${\pm}0.1%$ compared to the results of other works of the world.

The Effects of Hypercapnia and High Flow on Cerebral Metabolism During Cardiopulmonary Bypass (심폐바이패스 시 고탄산분압과 고관류법이 뇌대사에 미치는 영향)

  • 강도균;최석철;윤영철;최국렬;정신현;황윤호;조광현
    • Journal of Chest Surgery
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    • v.36 no.7
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    • pp.472-482
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    • 2003
  • Recent studies have demonstrated that cerebral desaturation during rewarming period of CPB was associated with postoperative neurologic dysfunction. The prevention of cerebral desaturation during CPB may reduce the incidences of neurologic and neuropsychological complications. The present study was prospectively undertaken to compare the clinical effects between two strategies (hypercapnic CPB and high flow CPB) to prevent cerebral desaturation for establishing a proper CPB technique. Material and Method: Thirty-six adult patients scheduled for elective cardiac surgery were randomized into either hypercapnic (Pa$CO_2$ 45~50mmHg, n=18) or high flow group (flow rate 2.75 L/ $m^2$/min and Pa$CO_2$ 35~40mmHg, n=18) during rewarming period of CPB. In each patient, middle cerebral artery blood flow velocity ( $V_{MCA}$), cerebral arteriovenous oxygen content difference (C(a-v) $O_2$), modified cerebral metabolic rate for oxygen (MCMR $O_2$), cerebral oxygen transport rate ( $T_{E}$ $O_2$), incidence of cerebral desaturation (internal jugular bulb blood oxygen saturation $\leq$ 50%), increased rate of S-100 $\beta$ concentration, and arterial and internal jugular bulb blood gas were measured during the five phases of the operation; Pre-CPB, CPB-10 min (steady-state CPB, nasopharyngeal temperature 29~3$0^{\circ}C$), Rewarm-1 (rewarming phase, nasopharyngeal temperature 33$^{\circ}C$), Rewarm-2 (nasopharyngeal temperature 37$^{\circ}C$), and CPB-off. Incidence of postoperative delirium and duration were assessed in all patients. All variables were compared between the two groups. Result: $V_{MCA}$ (157.88$\pm$10.87 vs 120.00$\pm$6.18%, p=0.006), internal jugular bulb $O_2$ saturation (68.01$\pm$2.75 vs 61.28$\pm$2.87%, p=0.03) and $O_2$ tension (41.01$\pm$2.25 vs 32.02$\pm$ 1,67 mmHg, p=0.03), and $T_{E}$ $O_2$(110.84$\pm$7.41 vs 81.15$\pm$8.11%, p=0.003) at rewarming periods were higher in the hypercapnic group than in the high flow group. C(a-v) $O_2$ (4.0$\pm$0.30 vs 4.84$\pm$0.38 mg/dL, p=0.04), COE (0.36$\pm$0.03 vs 0.42$\pm$0.03, p=0.04), increased rate of S- 100$\beta$ (391.67$\pm$23.40 vs 940.0$\pm$17.02%, p=0.003), and incidence of cerebral desaturation (2 vs 4 patients, p=0.04) at rewarming periods, and duration of postoperative delirium (18 vs 34 hr, p=0.02) were low in the hypercapnic group compared to the high flow group. Conclusion: These results indicate that hypercapnic CPB may provide relatively diminished cerebral injury and beneficial effects for cerebral metabolism relatively compared to high flow CPB.low CPB.

Tilt variation and wake turbulence in the otter board of a bottom trawl during fishing operations

  • KIM, Yong-Hae
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.53 no.4
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    • pp.337-348
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    • 2017
  • The tension of warp from trawler and sea-floor contact can generate tilt and wake turbulence around otter boards. Preliminary measurements of otter board tilt and 3-D flow velocity during bottom trawl operations were taken using a vector instrument to investigate the effects of wake turbulence at the trailing edge of the otter board. Tilt data (i.e., yaw, pitch, and roll) at 1 Hz and flow data (velocities in the towing, lateral, and vertical directions) at 16 Hz were analyzed to determine their periods and amplitudes using global wavelet and peak event analyses. The mean period (${\pm}standard$ deviation) of the tilt from the peak event analysis ($5{\pm}2s$) was longer or double than that of flow velocity ($3{\pm}2s$). The two periods also had a significant linear relationship. The turbulence rate of flow was 30-50% at the trailing edge and was closely related to roll deviation. The frequency of phase difference ratios (i.e., peak time differences between tilts and flow periods) was significantly different from random occurrence in two trials, possibly due to side tidal effects. However, in the other trials, flow peaks were random, as shown by the even peak times between tilts and flows. Future studies should focus on reducing tilt variation, wake turbulence, and bottom contact to stabilize otter board motion.

A Study on the factors of Quality variation for High Flowing Concrete in Site (고유동 콘크리트의 품질변동 요인에 관한 연구)

  • Kwon Yeong-Ho;Lee Hyun-Ho;Lee Hwa-Jin;Ha Jae-Dam
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.743-746
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    • 2004
  • This research investigates experimentally an effect on the properties of the high flowing concrete according to variations of concrete materials and site conditions. Variations of sensitivity test are selected items as followings; (1)Concrete temperature, (2)Unit water(Surface moisture of fine aggregate), (3)Fineness modulus of fine aggregate, (4)Addition ratio of high-range water reducing agent. And fresh conditions of the high flowing concrete should be satisfied with required range including slump flow$(65{\pm}5cm)$, 50cm reaching time of slump flow$(4\~10sec)$, V-box flowing time$(10\~20sec)$, U-box height(min.300mm) and air content$(4{\pm}1\%)$. As results of sensitivity test, material variations and site conditions should be satisfied with the range as followings; (1)Concrete temperature is $10\~20^{\circ}C$ (below $30^{\circ}C$), (2)Surface moisture of fine aggregate is within ${\pm}0.6\%$, (3)Fineness modulus of fine aggregate is $2.6{\pm}0.2$ and (4)addition ratio of high range water reducing agent is within $1\%$ considered flow-ability, self-compaction and segregation resistance of the high flowing concrete.

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Characteristic of PM10 Distribution Related to Precise Local Wind Patterns in Busan Metropolitan Area (상세 국지 기류 분포를 고려한 부산 지역 내 미세 먼지 분포 특성)

  • Hong, Seon-Hwa;Lee, Soon-Hwan
    • Journal of Environmental Science International
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    • v.26 no.12
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    • pp.1375-1387
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    • 2017
  • In order to investigate the $PM_{10}$ concentration trend and its characteristics over five different sub area in Busan from 2013 to 2015, data analysis with considering air flow distribution according to its topography was carried out using statistical methodology. The annual mean concentrations of $PM_{10}$ in Busan tend to decrease from $49.6{\mu}g/m^3$ in 2013 to $46.9{\mu}g/m^3$ in 2015. The monthly mean concentrations value of $PM_{10}$ were high during spring season, from March to May, and low during summer and fall due to frequent rain events. The concentration of $PM_{10}$ was the highest in five different sub-area in Busan. High concentration episodes over 90 percentile of daily $PM_{10}$ concentration were strongly associated with mean daily wind speed, and often occurred when the westerly wind or southwesterly wind were dominant. Regardless of wind direction, the highest correlation of $PM_{10}$ concentrations was observed between eastern and southern regions, which were geographically close to each other, and the lowest in the western and eastern regions blocked by mountains. Wind flow along the complex terrain in Busan is also one of the predominant factors to understand the temporal variation of $PM_{10}$ concentrations.

Design and Fabrication of an Electromagnetic Flowmeter (전자기유량계의 설계 및 제작)

  • Lim, Ki-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.10
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    • pp.1385-1392
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    • 2003
  • An electromagnetic flowmeter(EMF) was developed and its characteristics were compared with a commercial EMF. The developed EMF was designed as the 100 mm nominal diameter. A signal processing circuit was also developed for generating the magnetic field and converting the flow signal to flowrate and flow quantity. In order to obtain a more stable and reliable flow signal, the double magnetizing frequency was adopted for magnetizing the coil of the EMF. For the characterization of the developed EMF, the uncertainty of calibrator was estimated within $\pm$0.5 %. The evaluation procedure of the uncertainty followed the ISO Guide to the Expression of Uncertainty in Measurement. It was found that the flow signals between the electrodes were about $\pm$60-$\pm$300$\mu$V, which were sufficient for the discrimination of flowmeter and the protection of noise. The test results against the calibrator showed the good linearity in the range of 3 ㎥/h and 70 ㎥/h. A commercialized design of the EMF based on the current study will be technically more competitive in domestic and foreign market.

An Experiments Analysis of Comparison of Flow Gradients Across Disposable Arterial Perfusion Cannulas (일회용 각종 송혈관의 관류압차에 대한 비교실험)

  • Kim, Yo-Han;Kim, Hyeong-Muk
    • Journal of Chest Surgery
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    • v.19 no.1
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    • pp.18-24
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    • 1986
  • The mean perfusion pressure produced by 20 different design and size of disposable aortic perfusion cannulas [size range: 18F to 20F] at flow rates of 1 to 5 L/min was compared. A roller pump with perfusion tubing 10mm in inner diameter was used with a mixture of 0.9% normal saline and 100% glycerin [mixing ratio of 6.72:13.28] to make the viscosity as normal blood in 20oC as the test solution. Line pressure in these cannulas at a flow rate of 3L/min ranged from 13.2$\pm$4.47 to 157$\pm$1 34 mmHg in a case of absence of resistance, and from 11.4$\pm$1.14 to 227.2$\pm$4.47 mmHg in a case of presence of resistances 14 cannulas had gradients of less than 100Hg at a flow rate of 3L/min and 9 cannulas less than 100mmHg at 4L/min. The following results were obtained from this experimental study: .1] A wide range of line pressure was observed in disposable aortic perfusion cannulas currently in clinical use; 2] Some cannulas currently used for cardiopulmonary bypass in adults generated excessive line pressure; 3] Both the material and design affect function, with some designs safer than others. Cardiac surgeons should base the choice of aortic perfusion cannula on the best performance and safest design available to avoid cannula-related problems during operation.

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Associations Between Age, Cytogenetics, FLT3-ITD, and Marrow Leukemia Cells Identified by Flow Cytometry

  • Su, Long;Gao, Su-Jun;Tan, Ye-Hui;Han, Wei;Li, Wei
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.9
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    • pp.5341-5344
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    • 2013
  • Objectives: To explore the relationships between age, cytogenetic subgroups, molecular markers, and cells with leukemic aberrant immunophenotype in patients with acute myeloid leukemia (AML). Methods: In this study, we evaluated the correlations between age, cytogenetic subgroups (normal, balanced and unbalance karyotype), molecular mutations (NPM1, FLT3-ITD, and CEBPA mutations) and marrow leukemia cells (LC) identified by flow cytometry in 256 patients with de novo AML. Results: From age group 10-19 years to age group ${\geq}60$ years, the percentage of LC decreased from $67.0{\pm}18.4%$ to $49.0{\pm}25.1%$ (F=2.353, P=0.041). LC percentage was higher in patients with balanced karyotypes ($65.7{\pm}22.4%$), than those with unbalanced karyotypes ($46.0{\pm}26.6%$) (u=3.444, P=0.001) or a normal karyotype ($49.9{\pm}22.1%$) (u=5.093, P<0.001). Patients with FLT3-ITD ($64.3{\pm}19.5%$) had higher LC percentages compared with those without ($54.2{\pm}24.3%$) (u=2.794, P=0.007). Conclusions: Associations between age, cytogenetics, molecular markers, and marrow leukemia cells may offer beneficial information to understand the biology and pathogenesis of AML.

An Experimental Study on the Myocardial Protection Effects of the Cardioplegic Solution (Cardioplegic Solution의 심근보호 효과에 관한 실험적 연구)

  • 이종국
    • Journal of Chest Surgery
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    • v.13 no.4
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    • pp.321-337
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    • 1980
  • The increasing use of cardioplegic solution for the reduction of ischemic tissue injury requires that all cardiplegic solution be carefully assessed for any protective or damaging properties. This study describes functional, enzymatic and structural assessment of the efficiency of three cardioplegic solutions (Young & GIK, Bretschneider, and $K^{+}$ Albumin solution) in a Modified Isolated Rat Heart Model of cardiopulmonary bypass and ischemic arrest. Isolated rat heart were subjected to a 2-minute period of coronary infusion with a cold cardioplegic or a noncardioplegic solution immediately before and also at the midpoint of a 60-minute period of hypothermic ($10{\pm}1$. C) ischemic cardiac arrest. The results of this study were as follow: 1. Spontaneous heart beat after ischemic arrest occured 16 seconds later after Langendorff reperfusion in the Young & GIK group (n=6), and 40 second later in the Bretschneider group (n=6) and 6 minute later in the $K^{+}$ Albumin group (n=6), and 16 minute later in the control group (non-cardioplegia). A good recovery state of spontaneous heart beat was shown in the Young & GIK and Bretschneider groups. 2. The percentage of recorveries of heart function at 30 minute after postischemic working heart perfusion were : heart rate $91.6{\pm}3.1$% (P<0.01)m oeaj airtuc oressyre $83{\pm}3$% (P<0.01), coronary flow $70{\pm}8$% (P<0.05) and aortic flow flow rate $39{\pm}9.3$% (P<0.05) in the Young & GIK group. This percentage of recoveries of the Young & GIK group was significantly greater than the control group. In the Bretschneider group, the percentage of recoveries were : heart rate $87.8{\pm}7.5$%(P<0.05), peak aortic pressure $71{\pm}2.3$% (P<0.05) and aortic flow rate $33.2{\pm}6.6$%(P<0.05). hte percentage of recoveries were significantly greater than in the control group. In the $K^{+}$ Albumin group, recoveries of heart function were poor. 3. Total CPK leakage was $131.2{\pm}12.75$IU/30 min/gm. dry weight in the control group, $50.65{\pm}12.75$IU in the Young & GIK gruop, $69.40{\pm}32.21$Iu in Bretschneider group, and $103.65{\pm}15.47$IU in the $K^{+}$ Albumin group during the 30 minute postischemic Langendorff reperfusion. Total CPK leakage was significantly less (P<0.001) in the Young & GIK group, than in the control group. 4. Direct correlatin between percentage recovery of aortic flow rate and total amount of CPK leakage from Myocardium was noticed.(Correlation Coefficient r = 0.76, P<0.001). 5. Mild perivascular edema was the only finding of light microscopic study of myocardium after 60 minute ischemic arrest with cold cardioplegic solutions and hypothermla.

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Flow control of air blowing and vacuuming module using Coanda effect (코안다 효과를 이용한 에어 블로어와 흡입구의 유동 제어)

  • Jeong, Wootae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.115-121
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    • 2017
  • The efficiency of railway track cleaning vehicle for eliminating fine particulate matter (PM10 and PM2.5) in a subway tunnel depends strongly on the structure of the air blowing and suction system installed under the train. To increase the efficiency of underbody suction system, this paper proposes a novel method to use the Coanda effect for the air blower and dust suction module. In particular, through Computational Fluid Dynamics (CFD) analysis, the flow control device induced by the Coanda effect enables an increase in the overall flow velocity and to stabilize the flow distribution of the suction module at a control angle of $90^{\circ}$. In addition, the flow velocity drop at the edge of the air knife-type blower can be improved by placing small inserts at the edge of the blower. Those 4 modular designs of the dust suction system can help remove the dust accumulated on the track and tunnel by optimizing the blowing and suction flows.