• Title/Summary/Keyword: Transients

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Effects of Intervention for Health Promotion of Foreign Workers: A Systematic Review (외국인 근로자의 건강증진을 위한 프로그램의 효과 : 체계적 문헌고찰)

  • Kim, JinHee;Park, Seo Jin;Lee, Jina
    • Journal of the Korea Convergence Society
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    • v.9 no.9
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    • pp.407-420
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    • 2018
  • The purpose of this study was to investigate the effects and characteristics of program on health promotion with foreign worker in Korea. The study was conducted using the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Group. The final selected literature was varied in program and outcome variables. Therefore, it was difficult to quantitatively synthesize and it was analyzed through qualitative review. The findings indicate that health promotion programs for foreign workers reduced acculturation stress, depression and anxiety, and increased self-esteem. These findings provide scientific evidence for developing and using health promotion program of foreign workers. Futher development of a variety of health promotion programs and studies of effectiveness review for foreign workers in Korea.

Effect of PO43-, CO32- and F- anions on the electrochemical properties of the air-formed oxide covered AZ31 Mg alloy

  • Fazal, Basit Raza;Moon, Sungmo
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2017.05a
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    • pp.150.2-150.2
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    • 2017
  • This research was conducted to investigate in detail the effect of $PO_4{^{3-}}$, $CO_3{^{2-}}$ and $F^-$ anions on the electrochemical properties of the thin air-formed oxide film-covered AZ31 Mg alloy. In this work, native air-formed oxide films on AZ31 Mg alloy samples were prepared by knife-abrading method and the changes in the electrochemical properties of the air-formed oxide film were investigated in electrolytes containing 0.01 M, 0.05 M and 0.1 M of $PO_4{^{3-}}$, $CO_3{^{2-}}$ and $F^-$ anions. It was observed that the trend of open circuit potential (OCP) transients changed only in the solution containing $PO_4{^{3-}}$ ions. The Nyquist plots obtained from electrochemical impedance spectroscopy (EIS) showed that the resistance of the new surface films formed in fluoride ion containing bath increased with the increase in concentration of fluoride ions but the resistance of surface films formed in carbonate ion containing bath decreased with the increase in concentration of carbonate ions. The potentiodynamic polarization curves illustrated that under anodic polarization, there was growth of porous passive layer only in fluoride ion containing solution while the surface layer formed in phosphate and carbonate ion containing solutions lost its passivity at high anodic potential of $2.5V_{Ag/AgCl}$.

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Changes in the electrochemical properties of air-formed oxide film-covered AZ31 Mg alloy in aqueous solutions containing various anions

  • Fazal, Basit Raza;Moon, Sungmo
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2017.05a
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    • pp.96.2-96.2
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    • 2017
  • This research was conducted to investigate the electrochemical properties of the thin air-formed oxide film-covered AZ31 Mg alloy. In this work, native air-formed oxide films on AZ31 Mg alloy samples were prepared by knife-abrading method and the changes in the electrochemical properties of the air-formed oxide film were investigated in seven different electrolytes containing the following anions $Cl^-$, $F^-$, $SO{_4}^{2-}$, $NO_3{^-}$, $CH_3COO^-$, $CO{_3}^{2-}$ and $PO{_4}^{3-}$. It was observed from open circuit potential (OCP) transients that the potential initially decreased before gradually increasing again in the solutions containing only $CO{_3}^{2-}$ or $PO{_4}^{3-}$ ions, indicating the dissolution or transformation of the native air-formed oxide film into new more protective surface films. The Nyquist plots obtained from electrochemical impedance spectroscopy (EIS) showed that there was growth of new surface films with immersion time on the air-formed oxide film-covered specimens in all the electrolytes; the least resistive surface films were formed in fluoride and sulphate baths whereas the most protective film was formed in phosphate bath. The potentiodynamic polarization curves illustrated that passive behaviour of AZ31 Mg alloy under anodic polarization appears only in $CO{_3}^{2-}$ or $PO{_4}^{3-}$ ions containing solutions and at more than $-0.4V_{Ag/AgCl}$ in $F^-$ ion containing solution.

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Eugenol Inhibits ATP-induced P2X Currents in Trigeminal Ganglion Neurons

  • Li, Hai Ying;Lee, Byung-Ky;Kim, Joong-Soo;Jung, Sung-Jun;Oh, Seog-Bae
    • The Korean Journal of Physiology and Pharmacology
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    • v.12 no.6
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    • pp.315-321
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    • 2008
  • Eugenol is widely used in dentistry to relieve pain. We have recently demonstrated voltage-gated $Na^+$ and $Ca^{2+}$ channels as molecular targets for its analgesic effects, and hypothesized that eugenol acts on $P2X_3$, another pain receptor expressed in trigeminal ganglion (TG), and tested the effects of eugenol by whole-cell patch clamp and $Ca^{2+}$ imaging techniques. In the present study, we investigated whether eugenol would modulate 5'-triphosphate (ATP)-induced currents in rat TG neurons and $P2X_3$-expressing human embryonic kidney (HEK) 293 cells. ATP-induced currents in TG neurons exhibited electrophysiological properties similar to those in HEK293 cells, and both ATP- and $\alpha$, $\beta$-meATP-induced currents in TG neurons were effectively blocked by TNP-ATP, suggesting that $P2X_3$ mediates the majority of ATP-induced currents in TG neurons. Eugenol inhibited ATP-induced currents in both capsaicin-sensitive and capsaicin-insensitive TG neurons with similar extent, and most ATP-responsive neurons were IB4-positive. Eugenol inhibited not only $Ca^{2+}$ transients evoked by $\alpha$, $\beta$-meATP, the selective $P2X_3$ agonist, in capsaicin-insensitive TG neurons, but also ATP-induced currents in $P2X_3$-expressing HEK293 cells without co-expression of transient receptor potential vanilloid 1 (TRPV1). We suggest, therefore, that eugenol inhibits $P2X_3$ currents in a TRPV1-independent manner, which contributes to its analgesic effect.

The Semi-Implicit Numerical Scheme for Transient Two-Phase Flows on Unstructured Grids (과도 다차원 2상 유동 해석을 위한 비정렬 격자계에서의 Semi-Implicit 수치 해법 개발)

  • Cho, H.K.;Park, I.K.;Yoon, H.Y.;Kim, J.;Jeong, J.J.
    • Journal of Energy Engineering
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    • v.17 no.4
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    • pp.218-226
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    • 2008
  • A component-scale two-phase analysis code has been developed for a realistic simulation of two-phase flow transients in a light water nuclear reactor component. In the code, a two-fluid three-field model is adopted and the governing equations are solved on an unstructured mesh. For the numerical solution scheme, the semi-implicit method used in the RELAP5 code was selected, which has been proved to be very stable and accurate for most of practical applications. However, some modifications were needed for its application to an unstructured non-staggered grid. This paper presents the modified semi-implicit numerical method for unstructured grid and the preliminary results of the calculations.

A study on Power Quality Recognition System using Wavelet Transformation and Neural Networks (웨이블릿 변환과 신경회로망을 이용한 전력 품질 인식 시스템에 관한 연구)

  • Chong, Won-Yong;Gwon, Jin-Soo
    • Journal of the Institute of Convergence Signal Processing
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    • v.11 no.2
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    • pp.169-176
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    • 2010
  • Nonstationary power quality(PQ) signals which the Sag, Swell, Impulsive Transients, and Harmonics make sometimes the operations of the industrial power electronics equipment, speed and motion controller, plant process control systems in the undesired environments. So, this PQ problem might be critical issues between power suppliers and consumers. Therefore, We have studied the PQ recognition system in order to acquire, analyze, and recognize the PQ signals using the software, i.e, MATLAB, Simulink, and CCS, and the hardware. i.e., TMS320C6713DSK(TI), The algorithms of the PQ recognition system in the Wavelet transforms and Backpropagation algorithms of the neural networks. Also, in order to verify the real-time performances of the PQ recognition system under the environments of software and hardware systems, SIL(Software In the Loop) and PIL(Processor In the Loop) were carried out, resulting in the excellent recognition performances of average 99%.

Transient Diagnosis and Prognosis for Secondary System in Nuclear Power Plants

  • Park, Sangjun;Park, Jinkyun;Heo, Gyunyoung
    • Nuclear Engineering and Technology
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    • v.48 no.5
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    • pp.1184-1191
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    • 2016
  • This paper introduces the development of a transient monitoring system to detect the early stage of a transient, to identify the type of the transient scenario, and to inform an operator with the remaining time to turbine trip when there is no operator's relevant control. This study focused on the transients originating from a secondary system in nuclear power plants (NPPs), because the secondary system was recognized to be a more dominant factor to make unplanned turbine-generator trips which can ultimately result in reactor trips. In order to make the proposed methodology practical forward, all the transient scenarios registered in a simulator of a 1,000 MWe pressurized water reactor were archived in the transient pattern database. The transient patterns show plant behavior until turbine-generator trip when there is no operator's intervention. Meanwhile, the operating data periodically captured from a plant computer is compared with an individual transient pattern in the database and a highly matched section among the transient patterns enables isolation of the type of transient and prediction of the expected remaining time to trip. The transient pattern database consists of hundreds of variables, so it is difficult to speedily compare patterns and to draw a conclusion in a timely manner. The transient pattern database and the operating data are, therefore, converted into a smaller dimension using the principal component analysis (PCA). This paper describes the process of constructing the transient pattern database, dealing with principal components, and optimizing similarity measures.

Observation of Methyl Radical Recombination Following Photodissociation of CH3I at 266 nm by Time-Resolved Photothermal Spectroscopy

  • Suh, Myung-Koo;Sung, Woo-Kyung;Li, Guo-Sheng;Heo, Seong-Ung;Hwang, Hyun-Jin
    • Bulletin of the Korean Chemical Society
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    • v.24 no.3
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    • pp.318-324
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    • 2003
  • A time-resolved probe beam deflection (PBD) technique was employed to study the energy relaxation dynamics of photofragments produced by photodissociation of $CH_3I$ at 266 nm. Under 500 torr argon environment, experimental PBD transients revealed two energy relaxation processes; a fast relaxation process occurring within an acoustic transit time (less than 0.2 ㎲ in this study) and a slow relaxation process with the relaxation time in several tens of ㎲. The fast energy relaxation of which signal intensity depended linearly on the excitation laser power was assigned to translational-to-translational energy transfer from the photofragments to the medium. As for the slow process, the signal intensity depended on square of the excitation laser power, and the relaxation time decreased as the photofragment concentration increased. Based on experimental findings and reaction rate constants reported previously, the slow process was assigned to methyl radical recombination reaction. In order to determine the rate constant for methyl radical recombination reaction, a theoretical equation of the PBD transient for a radical recombination reaction was derived and used to fit the experimental results. By comparing the experimental PBD curves with the calculated ones, the rate constant for methyl recombination is determined to be $3.3({\pm}1.0)\;{\times}\;10^6\;s^{-1}torr^{-1}$ at 295 ± 2 K in 500 torr Ar.

SEPARATE AND INTEGRAL EFFECT TESTS FOR VALIDATION OF COOLING AND OPERATIONAL PERFORMANCE OF THE APR+ PASSIVE AUXILIARY FEEDWATER SYSTEM

  • Kang, Kyoung-Ho;Kim, Seok;Bae, Byoung-Uhn;Cho, Yun-Je;Park, Yu-Sun;Yun, Byoung-Jo
    • Nuclear Engineering and Technology
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    • v.44 no.6
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    • pp.597-610
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    • 2012
  • The passive auxiliary feedwater system (PAFS) is one of the advanced safety features adopted in the APR+, which is intended to completely replace the conventional active auxiliary feedwater system. With an aim of validating the cooling and operational performance of PAFS, an experimental program is in progress at KAERI, which is composed of two kinds of tests; the separate effect test and the integral effect test. The separate effect test, PASCAL ($\underline{P}$AF$\underline{S}$ $\underline{C}$ondensing Heat Removal $\underline{A}$ssessment $\underline{L}$oop), is being performed to experimentally investigate the condensation heat transfer and natural convection phenomena in PAFS. A single, nearly-horizontal U-tube, whose dimensions are the same as the prototypic U-tube of the APR+ PAFS, is simulated in the PASCAL test. The PASCAL experimental result showed that the present design of PAFS satisfied the heat removal requirement for cooling down the reactor core during the anticipated accident transients. The integral effect test is in progress to confirm the operational performance of PAFS, coupled with the reactor coolant systems using the ATLAS facility. As the first integral effect test, an FLB (feedwater line break) accident was simulated for the APR+. From the integral effect test result, it could be concluded that the APR+ has the capability of coping with the hypothetical FLB accident by adopting PAFS and proper set-points of its operation.

Development of TASS Code for Non-LOCA Safety Analysis Licensing Application (Non-LOCA 인허가 해석용 TASS 코드의 개발)

  • Yoon, Han-Young;Auh, Geun-Sun;Kim, Hee-Cheol;Kim, Joon-Sung;Park, Jae-Don
    • Nuclear Engineering and Technology
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    • v.27 no.1
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    • pp.53-66
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    • 1995
  • Since the current licensed system codes for Non-LOCA safety analysis are applicable only for a specific type PWR, it is necessary to develope a new system analysis code applicable for all apes of PWRs. As a R&D program, KAERI is developing TASS code as an interactive and faster-than-real-time code for the NSSS transient simulation of both CE and Westinghouse plane. It is flexible tool for PWR analysis which gives the user complete control over the simulation through convenient input and output options. In this paper the code applicability to Westinghouse ape plants was verified by comparing the TASS prediction to plant data of loss of AC power and loss of load transients, and comparing to the prediction of RELAP5/MOD3 for feedline break, locked rotor, steam generator tube rupture and steam line break accidents.

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