• 제목/요약/키워드: dampening

검색결과 40건 처리시간 0.029초

진동타입기의 서스펜션이 진동시스템에 미치는 영향에 대한 연구 (A Study on the Effect of Suspension of Vibro Pile Driver on Pile Driving System)

  • 이승현;김병일
    • 한국산학기술학회논문지
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    • 제8권4호
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    • pp.826-831
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    • 2007
  • 진동타입기에 의한 진동시스템에 대하여 서스펜션이 없는 경우와 서스펜션이 있는 경우에 대한 해석해를 나타내고 서스펜션이 진동시스템에 미치는 영향을 살펴보았다. 해석결과에 따르면 서스펜션이 있는 진동타입기의 진폭은 서스펜션이 없는 경우에 비해 서스펜션의 질량이 증가할수록 지반의 댐핑값이 감소할수록 증가하였다. 서스펜션이 있는 진동 타입기에 대해 해석을 통해 유도된 일률을 설계기준에 의한 일률과 비교해본 결과 일률은 지반의 댐핑값에 따라 최대값까지 증가했다가 감소함을 알 수 있었고 최대 일률값은 서스펜션의 질량이 커짐에 따라 증가함을 알 수 있었는데 일률은 설계기준에 의한 일률보다는 항상 작게 나타났다.

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The Use of Noise Dampening Mats to Reduce Heavy-Equipment Noise Exposures in Construction

  • Saleh, Sabah;Woskie, Susan;Bello, Anila
    • Safety and Health at Work
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    • 제8권2호
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    • pp.226-230
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    • 2017
  • The performance of sound barriers was evaluated to determine their technical effectiveness and practicality in reducing noise exposures to operating engineers in construction. Commercially purchased sound dampening mats (SDMats) were installed inside three heavy-equipment engine compartments. Sound pressure levels (SPLs) were measured before and after installing the SDMats while the equipment was on idle and full-throttle settings where it normally operates. SPLs inside the heavy-equipment operator cabs were significantly reduced by 5.6-7.6 dBA on the full-throttle setting following installation of the SDMats (p < 0.01). The evaluated engineering control intervention was simple to install, affordable, and substantially reduced the engine noise reaching the heavy-equipment operator, potentially reducing reliance on hearing-protection devices to protect construction workers from noise exposures.

Print Mottle : Causes and Solutions from Paper Coating Industry Perspective

  • Lee, Hak-Lae
    • 펄프종이기술
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    • 제40권5호
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    • pp.60-69
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    • 2008
  • The principal reasons for applying a pigment coating to paper are to improve appearance and printability. The pigment coating provides a surface that is more uniform and more receptive to printing ink than are the uncoated fibers and, in turn, both facilitates the printing process and enhances the graphic reproduction. The improvement in print quality is readily apparent, especially in image areas or when multiple colors are involved. Although pigment coating of paper is to improve the printability, coated paper is not completely free from printing defects. Actually there are a number printing defects that are observed only with the coated papers. Among the printing defects that are commonly observed for coated papers, print mottle during multi-color offset printing is one of the most concerned defects, and it appears not only on solid tone area but also half dot print area. There are four main causes of print mottle ranging from printing inks, dampening solution, paper, and printing press or its operation. These indicates that almost every factors associated with lithographic printing can cause print mottle. Among these variation of paper quality influences most significantly on print mottle problems in multicolor offset printing, and this indicates that paper is most often to be blamed for its product deficiency as far as print mottle problems are concerned. Furthermore, most of the print mottle problems associated with paper is observed when coated papers are printed. Uncoated papers rarely show mottling problems. This indicates that print mottle is the most serious quality problems of coated paper products. Overcoming the print mottle is becoming more difficult because the operating speeds of coating and printing machines are increasing, coating weights are decreasing, and the demands on high-quality printing are increasing. Print mottle in offset printing is caused by (a) nonuniform back trap of ink caused by a nonuniform rate of ink drying, referred as "back trap mottle, and (b) nonuniform absorption of the dampening solution. Furthermore, both forms of print mottle have some relationship to the structure of the coated layer. The surest way of eliminating ink mottling is to eliminate unevenness in the base paper. Coating solutions, often easier to put into practice, should, however, be considered. In this paper the principal factors influencing print mottle of coated papers will be discussed. Especially the importance of base paper roughness, binder migration, even consolidation of coating layers, control of the drying rate, types of binders, etc. will be described.

도공지 물성 변화와 IPA에 의한 잉크 유화가 인쇄 모틀에 미치는 영향 (The Effects of the Properties Changing of Coated Paper and Ink Emulsion of IPA on Printed Mottle)

  • 하영백;이의수;오성상;구철회;윤종태
    • 한국인쇄학회지
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    • 제26권2호
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    • pp.1-13
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    • 2008
  • Printed mottle of coated paper is one of the most common phenomenon and the most difficult problem in offset printing. Offset printing is processed mainly processed by the attractive properties between water and oil, so all inks for off-printing must work with dampening solution(water). It may cause the emulsion on the printing nip from the printing pressure. This study aimed to investigate the effect of emulsified inks on print mottle from emulsified cyan ink by force with each different IP A contents. We measured the print mottle by densitometer and image analysis method. The emulsified inks also give effect to now properties of inks and it caused more ink transfer rate, however, it caused low density of inks. Moreover the emulsified inks were spreaded to around of dots and cause the thinning density on the non-printing area like print mottle. The results showed that the emulsified inks also cause scumming on the printing result with little mistake of adjusting dampening solution and mostly decreasing dot reproduction. So we could find out the obvious effect of emulsified inks to print mottle.

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긍정정서와 긍정정서 반응 양식이 안녕감에 미치는 영향 (The effects of positive affect and response styles to positive affect on well-being)

  • 김경희;이희경
    • 한국심리학회지:학교
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    • 제16권3호
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    • pp.339-359
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    • 2019
  • 본 연구는 긍정정서와 긍정정서 반응 양식이 안녕감에 미치는 영향을 탐색하고자 하였다. Fredrickson(1998)의 '확장-구축 이론(Broaden-and-Build theory)'에 기반하여, 긍정정서와 긍정정서 반응 양식이 안녕감의 변화와 유의하게 관련이 되고, 안녕감의 변화에 이들 변인이 호혜적으로 영향을 미칠 것이라고 가정하였다. 단기종단연구를 통해 학부생과 대학원생 147명을 대상으로 긍정정서와 긍정정서 반응 양식, 안녕감을 측정하였고, 참가자들의 안녕감 기저선을 통제하여 변인간 관계를 확인하였다. 연구 결과, 긍정정서와 긍정정서 강화하기는 안녕감의 증가를 유의하게 예측하였으나, 긍정정서 가라앉히기는 안녕감을 유의하게 예측하지 못하였다. 또한 긍정정서와 안녕감의 관계를 긍정정서 강화하기가 부분적으로 매개하였으며, 긍정정서 강화하기와 안녕감의 관계를 긍정정서가 완전 매개하는 것으로 나타났다. 이로써 긍정정서와 긍정정서 강화하기는 서로 영향을 주고 받음으로써 안녕감을 증진시키는 호혜적 관계임을 확인하였다. 이러한 결과를 바탕으로 상담 실제에 대한 시사점과 연구의 제한점을 논하였다.

아동학대 예방교육이 부모의 긍정정서 반응, 양육 스트레스, 아동학대 잠재성에 미치는 영향: 무작위 대조군 사전·사후 연구 (The effects of child abuse prevention education on parents' response to positive emotion, parenting stress, and child abuse potential: A randomized controlled pretest posttest design)

  • 김미현;박부경
    • 한국간호교육학회지
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    • 제30권1호
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    • pp.19-28
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    • 2024
  • Purpose: The purpose of this study was to develop a child abuse prevention education program for parents. Furthermore, the aim was to investigate the impact of child abuse prevention education on parents' response to positive emotion, parenting stress, and potential for child abuse. Methods: A randomized controlled pretest posttest design was used. A total of 60 participants, who were parents with children aged 1~5 and attending 8 nurseries and kindergartens located in Daegu, were recruited. They were randomly assigned to an experimental group (n=30) and a control group (n=30). The collected data were analyzed by an independent t-test, paired t-test, and χ2-test along with descriptive statistics using IBM SPSS Statistics 25.0. Child abuse prevention education for the experimental group included four modules on child rights, understanding child abuse, proper child discipline, and positive parenting attitudes. Results: The experimental group showed a significant difference in positive rumination from the control group (t=2.15, p=.036). The experimental group reported a significant difference in dampening from the control group (t=-2.49, p=.016). Additionally, the experimental group reported a significant difference in parenting stress from the control group (t=-2.12, p=.038) and also reported significant differences in child abuse potential from the control group (t=-2.26, p=.028). Conclusion: The results of this study indicate that child abuse prevention education for parents can improve positive rumination, reduce dampening, and reduce parenting stress and child abuse potential. Therefore, this study is useful in demonstrating how parental susceptibility to child abuse can be decreased. Future studies should pursue long-term programs and counseling programs.

실인쇄 실험에 의한 이물질 발생 원인 분석 사례

  • 이만교;이재수
    • 한국펄프종이공학회:학술대회논문집
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    • 한국펄프종이공학회 2001년도 추계학술발표논문집
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    • pp.201-202
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    • 2001
  • 옵셋인쇄에서 종이로부터 나오는 이물질에 의한 인새 트러블은 자주발생되는 현상이다. 인쇄물 상에서 나타나는 이러한 현상은 주로 회색 반점이나 히키(Hickey, Catyes) 혹은 Blanket poling으로 나타난다. 원인에 따라 Dust, Linting, Picking, Delamination, Piling으로 나눌 수 있다. 인쇄에서 이물질의 발생에 영향을 주는 요소가 많고 일반적인 경우에는 복합적인 원인에 의한 경우가 많아 인쇄물만으로는 이물질의 종류나 발생 원인을 파악하기 어렵다. 본 연구는 자체 제작한 Test chart를 이용하여 실인쇄 실험을 함으로써 이물질의 종류와 발생 원인을 분석한 사레를 보고하고자 한다. Test chart의 구성은 동일 면적의 화선면적율 20, 50, 75, 100%를 갖도록 설계하였고, 인쇄중 잉크(1st oscillating roll). 습수통(Dampening founation solution), Blanket 표면온도를 측정하였으며, 일정 부수 인쇄 후 인쇄판, Blanket, 인쇄물을 회수하여 분석하였다.

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Modeling Approaches for Dynamic Robust Design Experiment

  • Bae, Suk-Joo
    • 한국경영과학회:학술대회논문집
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    • 한국경영과학회 2006년도 추계학술대회
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    • pp.373-376
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    • 2006
  • In general, there are three kinds of methods in analyzing dynamic robust design experiment: loss model approach, response function approach, and response model approach. In this talk, we review the three modeling approaches in terms of several criteria in comparison. This talk also generalizes the response model approach based on a generalized linear model. We develop a generalized two-step optimization procedure to substantially reduce the process variance by dampening the effect of both explicit and hidden noise variables. The proposed method provides more reliable results through iterative modeling of the residuals from the fitted response model. The method is compared with three existing approaches in practical examples.

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텅스텐 CMP에서 산화제 영향에 관한 연구 (A Study on Oxidizer Effects in Tungsten CMP)

  • 박범영;이현섭;박기현;정석훈;서헌덕;정해도;김호윤;김형재
    • 한국전기전자재료학회논문지
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    • 제18권9호
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    • pp.787-792
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    • 2005
  • Chemical mechanical polishing(CMP) has become the process of choice for modem semiconductor devices to achieve both local and global planarization. CMP is a complex process which depends on numerous variables such as macro, micro and nano-geometry of pad, relative velocity between pad and wafer stiffness and dampening characteristics of pad, slurry, pH, chemical components of slurry, abrasive concentration, abrasive size, abrasive shape, etc. Especially, an oxidizer of chemical components is very important remove a target material in metal CMP process. This paper introduces the effect of oxidizer such as $H_2O_2,\;Fe(NO_3)_3\;and\;KIO_3$ in slurry for tungsten which is used in via or/and plug. Finally the duplex reacting mechanism of $oxidizer(H_2O_2)$ through adding the $catalyst(Fe(NO_3)_3)$ could acquire the sufficient removal rate in tungsten CMP.