• Title/Summary/Keyword: TIG

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Welding Fume and Metals Exposure Assessment among Construction Welders (건설현장 용접직종별 용접흄 및 금속류 노출 실태)

  • Park, Hyunhee;Park, Hae Dong;Jang, Jae-kil
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.26 no.2
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    • pp.147-158
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    • 2016
  • Objectives: The objective of this study was to evaluate the assessment of exposure to welding fume and heavy metals among construction welders. Methods: Activity-specific personal air samplings(n=206) were carried out at construction sites of three apartment, two office buildings, and two plant buildings using PVC(poly vinyl chloride) filters with personal air samplers. The concentration of fumes and heavy metals were evaluated for five different types of construction welding jobs: general building pipefitter, chemical plant pipefitter, boiler maker, ironworker, metal finishing welder. Results: The concentration of welding fumes was highest among general building pipefitters($4.753mg/m^3$) followed by ironworkers($3.765mg/m^3$), boilermakers($1.384mg/m^3$), metal finishing welders($0.783mg/m^3$), chemical pipefitters($0.710mg/m^3$). Among the different types of welding methods, the concentration of welding fumes was highest with the $CO_2$ welding method($2.08mg/m^3$) followed by SMAW(shield metal arc welding, $1.54mg/m^3$) and TIG(tungsten inert gas, $0.70mg/m^3$). Among the different types of workplace, the concentration of welding fumes was highest in underground workplaces($1.97mg/m^3$) followed by outdoor($0.93mg/m^3$) and indoor(wall opening as $0.87mg/m^3$). Specifically comparing the workplaces of general building welders, the concentration of welding fumes was highest in underground workplaces($7.75mg/m^3$) followed by indoor(wall opening as $2.15mg/m^3$). Conclusions: It was found that construction welders experience a risk of expose to welding hazards at a level exceeding the exposure limits. In particular, for high-risk welding jobs such as general building pipefitters and ironworkers, underground welding work and $CO_2$ welding operations require special occupational health management regarding the use of air supply and exhaust equipment and special safety and health education and fume mask are necessary. In addition, there is a need to establish construction work monitoring systems, health planning and management practices.

Using ultrasound infrared thermography to detect defects in lap joint Friction stir welding (초음파 적외선 열화상을 이용한 마찰교반용접부의 결함 검출)

  • Park, Hee-Sang;Choi, Man-Young;Park, Jung-Hak;Lee, Young-Ho;Choi, Won-Young;Ko, Jun-Bin;Choi, Won-Doo
    • Proceedings of the KWS Conference
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    • 2009.11a
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    • pp.67-67
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    • 2009
  • 알루미늄 합금 재질은 무게의 경량화와 기계적강도가 우수하며 다른 비철금속에 비하여 값이 저렴한 장점이 있다. 현재 산업현장에서 활용하는 가장 흔한 접합법으로 TIG, RSW 등과 같은 용융 용접법을 현재는 많이 사용 하고 있지만 열전도도가 높아 열 확산이 빠르고, 이에 따라 모재의 팽창이 일어나 열변형을 유발하며, 산화피막은 그 내부에 함유된 결정수가 아크용접 중 분해되어 수소를 방출함으로 기공이 발생하여 부도체로 저항용접시 전도성을 방해하는 등의 문제를 발생시킨다. 또한 철에 비해 4배정도 큰 전기전도율에 따라 저항용접시 대전류를 사용해야 하는 등의 문제점이 발생하고 있다. 이와 같은 알루미늄 합금의 용융용접 과정에서 발생하는 단점을 극복하는 기술로 고상접합 방법인 마찰교반용접법(Friction Stir Welding)이 활용되고 있다. FSW는 1991년 영국의 TWI에서 개발된 최신 용접법으로 모재를 용융점 아래에서 고상용접시키는 방법으로 용융에 따른 열변형과 흄가스(hume gas)와 스패터(spatter)를 억제시켜 주는 친환경적인 용접법이다. 이러한 마찰교반용접의 기술은 그동안 특허에 따른 로열티가 산업현장에서 사용하는데 문제가 되었으나 특허보호 기간인 20년이 1년정도의 기간밖에 남지 않은 상황에서 그 사용은 날로 증가하리라 본다. 이러한 마찰교반용접부의 결함을 평가하는 방법에는 UT, RT 등이 활용되고 있으나 얇은 박판에서의 결함검출은 용이하지 않다. 이리한 문제점을 해결하기위하여 초음파 가진을 이용한 적외선 열화상 검출 기법을 이용하여 마찰교반용접부의 결함 검출 가능성을 연구하였다. 20kHz의 주파수를 400Watt로 가진시켜 겹치기(lap joint) 마찰교반용접이된 A6061-T6의 용접부에 초음파를 입사하였을 때 발생하는 열을 적외선 열화상 카메라를 이용하여 측정함으로써 마찰교반겹치기 용접부의 결함 검출에 활용하였다. 용접부에 초음파를 입사하였을 때 부분적으로 온도차이가 발생하였고, 그에 따른 열화상을 검출 할 수 있었다. 이러한 열화상과 실제 시험편의 용접부의 강도를 평가하기 위하여 인장시험을 하였다. 그 결과 초음파 적외선 열화상 검출에서 발열부위가 나타난 부분이 인장시험에서 낮은 인장강도를 보였다.

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Die Übersicht des rechtliche Struktur über die Rechtsschutzversicherung (법무비용보험의 법적 구조의 개관 - 독일 입법례를 중심으로 -)

  • Kim, Eun-Kyung
    • Journal of Legislation Research
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    • no.44
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    • pp.315-342
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    • 2013
  • Die Rechtsschutzversicherung ist als eine echte Schadenversicherung eine neue Versicherung, die $Spezialit{\ddot{a}}t$ des versichertes Risikos hat. Das bedeutet, dass der Rechtschutzversicherer nur bestimmte vertraglich vereinbarte Risiken $tr{\ddot{a}}gt$. Diese Risiken sind in den Allgemeinen Bedingungen $f{\ddot{u}}r$ die Rechtsschutzversicheurng (ARB) im Zusammenhang mit Versicherungsvertragsgesetz (VVG) ${\S}$ 125 exact beschrieben. VVG ${\S}$ 125 spricht allegemein von Leistung des Versicherers im vereinbarten versicherten Umfang. Entscheidend ist also die Vereinbarung in den ARB, welche in ${\S}$ 1 die Kostentragung $f{\ddot{u}}r$ den Versicherten als Hauptleistung des Versicherers beschrieben ist. Also in den VVG ${\S}{\S}$ 125 bis 129 gibt es keine Definition ${\ddot{u}}ber$ die Sparte der Rechtsschutzversicherung, jedoch mindestens es $w{\ddot{a}}re$ $m{\ddot{o}}glich$, diese Sparte zu definieren. Um die $k{\ddot{u}}nftige$ Produktentwicklung nicht zu hindern, $enth{\ddot{a}}lt$ die Vorschrift keine gesetzliche Definition der Rechtsschutzversicherung nach Angabe der amtlichen $Begr{\ddot{u}}ndung$. Weil in Korea die Rechtsschutzversicherung relativ neu in Versicherungsmarket ist, sind daher VVG ${\S}{\S}$ 125 ein gutes gesetzgeberisches Vorbild, um pragmatisch und auch dazu rechtswissenschaftlich zu diskutieren und diese fsetzustellen. Im Schritt von Ausdehnungen der juristischen Dienstleistung $w{\ddot{a}}re$ es $n{\ddot{o}}tig$, zu betrachten, wie Leistungsumfang des Versicherers in der Rechtsschutzversicherung erweitert werden kann. And noch dazu ist die Informationspflicht des Versicherers in Hinsicht auf Versicherungsunfall und Leistungsumfang noch weitert zu ${\ddot{u}}berlegen$, weil diese Sparte der Rechtsschutzversicherung noch professioneller als die anderen Versicherungsbereiche ist.

Spectral Characteristics of Sea Surface Height in the East Sea from Topex/Poseidon Altimeter Data (Topex/Poseidon에서 관측된 동해 해수면의 주기특성 연구)

  • 황종선;민경덕;이준우;원중선;김정우
    • Economic and Environmental Geology
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    • v.34 no.4
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    • pp.375-383
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    • 2001
  • We extracted sea surface heights(SSH) from the TopexJPoseidon(T/P) radar altimeter data to compare with fhe SSH estimated from in-situ lide gauges(T/G) at Ulleungdo, Pohang, and SockcholMucko sites. Selection criteria such as wet/dry troposphere, ionosphere, and ocean tide were used to estimate accurate SSH. For time series analysis, the one-hour interval tide gauge SSHs were resampled al lO-day interval of the satellite SSHs. The ocean tide model applied in the altimeter data processing showed periodic aliasings of 175.5 day, 87.8 day, 62J day, 58.5 day, 49.5 day and 46.0 day, and, hence, the ZOO-day filtering was applied to reduce these spectral noises. Wavenumber correlation analysis was also applied to extract common components between the two SSHs, resulting in enhancing the correlation coefficient(CC) dramatically. The original CCs between the satenite and tide gauge SSHs are 0.46. 0.26, and 0.]5, respectively. Ulleungdo shows the largest cc bec;luase the site is far from the coast resulting in the minimun error in the satellite observations. The CCs were then increased to 0.59, 030, and 0.30, respectively, after 200.day filtering, and to 0.69, 0.63. and 0.59 after removing inversely correlative components using wavenumber correlation analysis. The CCs were greatly increased by 87, 227, and 460% when the wavenumber correlation analysis was followed by 2oo-day filtering, resulting in the final CCs of 0.86, 0.85, 0.84, respectively. It was found that the best SSHs were estimated when the two methods were applied to the original data. The low-pass filtered TIP SSHs were found to be well correlated with the TIG SSHs from tide gauges, and the best correlation results were found when we applied both low-pass filtering and spectral correlation analysis to the original SSHs.

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Mono-Rifampicin-Resistant Pulmonary Tuberculosis (Rifampicin단독내성 폐결핵)

  • Shim, Tae-Sun;Lee, Ki-Man;Lim, Chae-Man;Lee, Sang-Do;Koh, Youn-Suck;Kim, Woo-Sung;Kim, Dong-Soon;Kim, Won-Dong
    • Tuberculosis and Respiratory Diseases
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    • v.46 no.5
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    • pp.618-627
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    • 1999
  • Background : Rifampicin (RFP) is a key component of the antituberculous short-course chemotherapy. Usually the RFP resistant M.tuberculosis is also resistant to isoniazid (INH), so the RFP resistance is the marker of multi-drug resistant (MDR) tuberculosis. But unusual cases of mono-RFP-resistant tuberculosis have been recently reported with increasing frequency, especially associated with HIV infection in western countries. Therefore, we conducted a retrospective study to investigate the frequency, causes, and the clinical characteristics of mono-RFP-resistant tuberculosis in Korea. Methods : Of the bacteriologically confirmed and susceptibility-proven 699 pulmonary tuberculosis patients (921 isolates) who visited Asan Medical Center from January 1990 to August 1997, eighteen patients with INH-susceptible and RFP-resistant tuberculosis were evaluated. Previous history of tuberculosis, antituberculous drug compliances, associated systemic illness, drug susceptibility patterns, and clinical outcomes were analysed. And rpoB gene sequencing was done in 6 clinical isolates of M. tuberculosis. Results : The mean age of 18 patients was $43{\pm}14$ years, and the sex ratio is 12:6 (M : F). Sixteen (89%) patients had previous history of tuberculosis. None had diagnosed gastrointestinal disorders, and 2 HIV tests that were performed came out negative. Susceptibility tests were done repeatedly in eleven patients, and six (55%) were mono-RFP resistant repeatedly while five (45%) evolved to MDR tuberculosis. Eight (44%) patients were cured, six (33%) failed, three (17%) were lost to follow-up, and the other one is now on treatment. rpoB gene sequencing showed 5 mutations, codon 531 TCG to TIG mutation in 4 isolates and 526 CAC to TAC in 1 isolate. Conclusion : The clinical characteristics of mono-RFP resistant tuberculosis were similar to that of MDR tuberculosis in Korea where the HIV infection rate is lower than western countries. But some patients with mono-RFP-resistant tuberculous could be cured by primary drug regimens including RFP, suggesting that mono-RFP-resistant tuberculous is a different entity from MDR tuberculosis.

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Inhalt und Probleme von dem Entwurf des Änderungsgesetzes zum koreanischen Verwaltungsprozessgesetz - Zugleich eine kritische Betrachtung zum Änderungsgesetz für Reform und Entwicklung des Verwaltungsprozesses - (행정소송법 개정안의 내용 및 문제점 - 특히 행정소송의 개혁과 발전을 위한 비판적 고찰을 중심으로 -)

  • Chung, Nam-Chul
    • Journal of Legislation Research
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    • no.44
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    • pp.283-314
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    • 2013
  • Das koreanische Verwaltungsprozessgesetz (KVwPG) wurde am 24. 8. 1951 kodifiziert. Es hat bisher mehrmals $ge{\ddot{a}}ndert$. Der Regierungsentwurf des KVwPG-${\ddot{A}}nderungsgesetzes$ vom 30. 3. 2013, ist fast $drei{\ss}ig$ jahre nach der Novellierung des KVwPGs 1984 erfolgt und auch spiegelt sich die Erfolge der $Bem{\ddot{u}}hungen$ in Literatur und Rechtsprechung wider. Aber es gibt nicht nur einige Unterschiede zwischen dem Regierungsentwurf und dem Entwurf der Kommission des Justizministeriums zur ${\ddot{A}}nderung$ des KVwPG (dem sog. Kommissionsentwurf), sondern auch der Regierungsentwurf ist theoretisch nicht problemlos. Vor allem sind Begriff und Umfang der neuen Klagebefugnis nicht klar. Des weiteren sind in ${\S}$ 12 des Regierungsentwurfs die Klagebefugnis mit dem $Rechtsschutzbed{\ddot{u}}rfnis$ identisch gesehen. Der $Rechtsschutzbed{\ddot{u}}rfnis$ nach ${\S}$ 12 Satz 2 des Regierungsentwurfs kann aus meiner Sicht relativ eng ausgelegt. Die $Einf{\ddot{u}}hrung$ der Verpflichtugnsklage in den Regierungsentwurf ist sehr gut, aber es kann trotzdem als problematisch angesehen werden dass Feststellungsklage der Rechtswidrigkeit der Unterlassung und Anfechtungsklage gegen Ablehnung bestehen noch. Der Begriff der Unterlassung ist $unn{\ddot{o}}tig$ und auch strikt. $Vorl{\ddot{a}}ugier$ Rechtsschutz des Regierungsentwurfs ist unter dem Gesichtpunkt der Rechtsschutz der $B{\ddot{u}}rger$ noch zu verbessern, aber doch das Modell des japanischen Verwaltungsprozessgesetzes darf nicht befolgt werden. Aufbau und System des $vorl{\ddot{a}}ufigen$ Rechtsschutzes sind auch nicht eindeutig. Nach Gegenstand und Klageart muss das Institut des $vorl{\ddot{a}}ufigen$ Rechtsschutzes in Ordnung gebracht werden. Es ist nicht ${\ddot{u}}berzeugend$ dass die $Einw{\ddot{a}}nde$ gegen die $Einf{\ddot{u}}hrung$ der vorbeugenden Unterlassung mit dem Gewaltenteilungsprinzip und der $Eigenst{\ddot{a}}ndigkeit$ der Verwaltung erhoben sind. $Dar{\ddot{u}}ber$ hinaus ist ADR (Alternative Dispute Resolution) zu beachten. In Bezug darauf ist Rechtgrundlage $f{\ddot{u}}r$ Mediation in der Verwaltungsgerichtsbarkeit zu stellen.