• 제목/요약/키워드: Defect prevention

검색결과 131건 처리시간 0.025초

효율적 내수면 안전관리 : 수난구호 및 수상안전을 중심으로 (Efficient Safety Management in Inland Waters: Focused on Water Relief and Water Safety)

  • 정철민;양기근
    • 한국콘텐츠학회논문지
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    • 제15권3호
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    • pp.101-113
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    • 2015
  • 본 연구의 목적은 국내 내수면 안전관리 실태를 살펴보고 그 문제점을 진단하여 내수면에서의 인명사고를 예방하고 인명피해를 최소화하기 위한 방안을 마련하기 위한 것이다. 현재 내수면 안전관리의 문제점은 크게 4가지 측면으로 분석된다. 첫째, 내수면 안전관리를 총괄하는 법령 부재와 같은 "법률적 측면", 둘째, 내수면 안전사고 예방을 위한 교육프로그램 부재와 수난구조 전문가 부족과 같은 "학습적 측면", 셋째, 수난사고 신고체계 분산과 사고대응에 있어서의 민관 파트너십의 부족과 같은 "협력적 측면", 넷째, 내수면 수난사고에 대한 현장대응 능력 및 전문성 부족과 안전관리체계의 분산 중첩에 따른 "현장대응성 측면"이다. 이러한 문제점의 개선을 위해 경기도 및 강원도 수상레저 종사자 및 이용자에 대한 설문과 그 분석을 토대로 개선방안을 모색하였다. "법률적 측면"에서는 '내수면 수상안전관리에 관한 특별법(가칭)'제정, "학습적 측면"에서는 내수면 안전교육 프로그램 개발과 수난사고 전문가 양성, "협력적 측면"에서는 내수면 안전사고 통합 상황관리 운영시스템 마련과 안전네트워크 활성화 및 민관 파트너십 재정립, "현장대응성 측면"에서는 현장대응 능력과 전문성 확보 및 소방중심의 내수면 안전관리 통합 등을 제시하였다.

An Acoustic Analysis of Noise Environments during Mobile Device Usage

  • Park, Hyung Woo
    • International journal of advanced smart convergence
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    • 제6권2호
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    • pp.16-23
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    • 2017
  • In contemporary modern society, people are constantly exposed to many kinds of noise, such as that from machinery, aircraft, construction sites, or road traffic. Noise is considered one of the most indispensable and influential parts of human life. This study investigates the acoustic characteristics of noise transfer from external sources to the human ear. For this study, we measured and analyzed various types of noise environments, installed monitoring speakers in a semi-anechoic room, and conducted intentional noise-filled experiments. In this environment, the size of the sounds generated by use of a portable device was also measured and the SNR (signal to noise ratio) calculated to study the influence of the noise. As sound is transmitted to the ear and the human body, it affects not only auditory damage but also other parts of the body. In this paper, we propose a proper SNR for noise emitted by portable IT equipment to prevent hearing loss when IT equipment is used.

전기장 이론을 이용한 3차원 단조공정에서의 예비형상 설계 (The Optimal Design of Preform in 3-D Forging by using Electric Field Theory)

  • 신현기;이석렬;박철현;양동열
    • 소성∙가공
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    • 제11권2호
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    • pp.165-170
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    • 2002
  • The preform design of forging processes plays a key role in improving product qualities, such as defect prevention, dimensional accuracy and mechanical strengths. In the industry, preforms are generally designed by the iterative trial-and-error approach, but it results in significant tooling cost and time. It is thus necessary to minimize lead-time and human intervention through an effective preform design method. In this paper, the equi-potential lines designed in the electric field are introduced to find the preform shape, and then the optimization process is used to choose the equi-potential lines that will keep the die wear to a minimum Because, in the forging process, the die wear is a function of various important factors, such as forming stress and strain, microstructure and mechanical properties of a Product.

Nd:YAG 레이저의 펄스 제어에 의한 마그네슘 합금 용접부의 결함 방지에 관한 연구 (Study of Defect Prevention on Weld Zone of Magnesium Alloy by Pulse Control of Nd:YAG Laser)

  • 김종도;이정한;김장수
    • 한국정밀공학회지
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    • 제27권1호
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    • pp.99-104
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    • 2010
  • Magnesium and magnesium alloys, the lightest structural materials, have been received plenty of global attention recently. These alloys could be applied in various fields, especially the electronics industry, because of their excellent electromagnetic interference shielding. However, the welding technique of magnesium alloys has not been established. This study is related to the welding of AZ31B magnesium alloy by a short-pulsed a Nd:YAG laser. Two types of pulse waves, square pulse and variable pulse, were used to control weld defects. Results show that the crack and porosity, generated in the weld, had not been controlled by general square pulse. But through the application of variable pulse, the defects could be prevented and the good weld zone was obtained.

X-65 배관용 재료의 손상해석 (Analysis of Gas Pipelines Damaged in X-65 Steels)

  • 진영준
    • 한국산업융합학회 논문집
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    • 제8권4호
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    • pp.197-204
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    • 2005
  • It is well known that pipelines have the highest capacity and are the safest and least environmentally disruptive form of transporting oil and gas. However, pipeline damages caused by both internal and external corrosion is a major concern threatening the reliability of oil and gas transportation and the soundness of pipeline structure. In this study, we estimated the expected allowable damage defect by comparing the ASTM B31G code which has been developed as the evaluation method of reliability and incident prevention of damaged pipelines based on the amount of loss due to corrosion and the yield strength of materials to a modified theory considering diverse detailed corrosional forms. Furthermore, we suggested the method that estimates the expected life span of used pipelines by utilizing the reliability method based on major variables such as, the depth and length of damage and corrosional rate affecting the life expectancy of pipelines.

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Nb 첨가 오스테나이트계 스테인레스강의 연속주조시 표면크랙 형성기구 및 제어 (Formation Mechanism of Surface Crack and Its Control on Continuously Cast Slabs of Nb-containing Austenitic Stainless Steel)

  • 심상대;김선구
    • 한국주조공학회지
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    • 제21권5호
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    • pp.280-285
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    • 2001
  • Nb-containing austenitic stainless steel is widely used as exhaust frame and diffuser assembly in power plant. However, this steel is known to be difficult to produce by the continuous casting process due to the surface cracks. Therefore, the continuous casting technology was developed for the prevention of the surface cracks on CC slabs. Precipitates and the analysis of heat trasfer in a slab were investigated in order to find out the formation mechanism of surface cracks on cc slabs It was found that surface cracks are occurred due to the NbC precipitates, which are formed along the grain boundaries around $800^{\circ}C$. The secondary cooling pattern has been developed to produce the defect free CC slabs of Nb-containing austenitic stainless steel.

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건설업에서의 시공FMEA적용 방안 연구 (Approach to Method of Process Failure Mode and Effect Analysis for Construction Industry)

  • 김윤성
    • 한국건설관리학회:학술대회논문집
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    • 한국건설관리학회 2002년도 학술대회지
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    • pp.271-274
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    • 2002
  • 산업체에서 이미 보편화되어 온 FMEA기법의 목적은 발생가능성이 있는 하자형태를 파악하고, 고객에게 미칠 고장 발생 요인을 우선 순위별로 사전에 제거하도록 이행하는 예방조치의 한 수단이다. FMEA는 초기 단계(Design 개념 설정시)에서 작성하는 Design FMEA와 양산되기 전에 시기 적절하게 작성하는 Process FMEA의 두 종류가 있다. (설계기능이 없는 공급자에게는 Process FMEA만 해당) 본 연구에서는 Process FMEA를 건설업의 시공분야에 적용하여 품질향상의 신뢰성을 높이고 Life Cycle Analysis, Risk Analysis 등의 기초자료로 활용이 가능한 기본자료(DATA)를 축적할 수 있는 방안을 연구하였다.

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강원도 중소기업의 제조물책임법 대책에 대한 연구 (A Case Study on PL Management in Small and Medium-Sized Firms of Gangwon-Do Province)

  • 박노국;이성호
    • 대한안전경영과학회지
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    • 제10권3호
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    • pp.99-107
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    • 2008
  • Product liability(PL) is the producer's compensation to customers for damage incurred by product defects. This paper studies on the organizational culture, promotion process, system construction, system level, product safety review, product safety assurance, system operation, and its effectiveness and necessity of recognition for the PL system of small and medium-sized firms in Gangwon-Do province. The results show that the firms have product safety regulations, but the number of firms which its employees understand the regulations is less than the number of firms which do not understand. Also the number of firms which is preparing PL prevention and insurance, and counterplan for accidents seems to be not in large numbers.

카본 도포에 따른 Cu-Epoxy 접촉면에서 발생하는 크랙방지에 관한 연구 (A Study on the Prevention of Crack Generated in Interface Cu and Epoxy with Painting of Carbon)

  • 송재주;김성훈;황종선;박종광;한병성
    • 한국전기전자재료학회논문지
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    • 제14권7호
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    • pp.578-583
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    • 2001
  • The bushing for high voltage and large and power should endure weight of itself and force of pushing from contact with circuit breaker. Like this, epoxy mold bushing has to be strong without fault. However, the external circumstances and internal factors was caused by partial discharge, flashover and dielectric breakdown. Therefore, to remove external factor of defect and to prevent the internal cracks and cavity generated from the contraction on interface of Cu-Epoxy, we should form semi-conductive layer on Cu bar by carbon. Then, the PD properties and the insulation qualities of epoxy mold type bushing was able to improved by roles of cushions for the direction of diameter and by effects fo natural sliding like as separated from conductor for the direction of length. So, in this work, we could prove the method of semi-conductive layer in making the long conductor.

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Invasive cervical resorption: treatment challenges

  • Kim, Yookyung;Lee, Chan-Young;Kim, Euiseong;Roh, Byoung-Duck
    • Restorative Dentistry and Endodontics
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    • 제37권4호
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    • pp.228-231
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    • 2012
  • Invasive cervical resorption is a relatively uncommon form of external root resorption. It is characterized by invasion of cervical region of the root by fibrovascular tissue derived from the periodontal ligament. This case presents an invasive cervical resorption occurring in maxillary lateral incisor, following damage in cervical cementum from avulsion and intracoronal bleaching procedure. Flap reflection, debridement and restoration with glass ionomer cement were performed in an attempt to repair the defect. But after 2 mon, more resorption extended apically. Considering root stability and recurrence potential, we decided to extract the tooth. Invasive cervical resorption in advanced stages may present great challenges for clinicians. Therefore, prevention and early detection must be stressed when dealing with patients presenting history of potential predisposing factors.