• 한국레이저가공학회지
• /
• 제8권3호
• /
• pp.27-30
• /
• 2005

Nowadays, most automotives companies are making use of laser welding in car body assembly shop. But even though laser welding is better than resistance spot welding in many points, its application has been limited to special technology for manufacturing. The paper introduces in the field of remote welding system (RWS) to improve the process efficiency of laser welding. Positioning time of RWS between welding stitches is dramatically reduced to zero. It is a kind of solutions to generalize laser welding in mass production. This RWS consists of fiber laser, industrial robot and 3-axis scanner.

• 대한토목학회논문집
• /
• 제26권3C호
• /
• pp.219-228
• /
• 2006

본 연구에서는 화재시나리오에 따른 터널구조물의 시공재료별 단면손실과 폭렬현상을 파악하고자 터널구조물 시공재료별로 시험체를 제작한 후 모의 화재시험을 수행하였다. 시공재료별로 화재시험을 수행한 결과, 모든 시공재료에서 RABT 화재곡선보다 RWS 화재곡선에서 단면손실이 다소 크게 발생하였다. 특히, RWS 화재곡선에서 나타나는 $1,200^{\circ}C$ 이상의 고온으로 인한 융해는 시공재료의 단면손실에 주요한 영향요인으로 작용하였다. 철근 보강 구조물은 무근 구조물에 비해 단면손실이 적은 것으로 나타났다. 숏크리트의 경우 화재 시나리오에 따른 단면손실의 차이가 가장 크게 발생하였다. 가열시험 도중에 가열면을 실시간 관찰한 결과, RABT에서의 재료 손상은 폭렬과 탈락에 의해 발생한 반면 RWS에서는 초기에는 RABT와 유사하나 가열개시후 약 50분 이후의 재료 손상은 폭렬과 탈락이 아닌 융해에 의한 것을 알 수 있었다.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2006년도 춘계 학술발표회 논문집
• /
• pp.960-969
• /
• 2006

In this study, a series of fire tests was carried out to evaluate fire-induced damage to structural members in tunnels. From the tests, the loss amount of concrete materials by the RWS fire scenario was slightly bigger than by the RABT fire scenario. Especially under the RWS fire scenario where the maximum temperature is over 1,200, the loss of concrete materials was mainly induced by melting. Generally, the loss of materials in reinforced concrete was slightly smaller than that in unreinforced concrete. Depending upon an applied fire scenario, fire-induced damage to shotcrete was quite different. From the real-time investigation of a specimen surface by a digital camcorder, it was proved that the material loss under the RABT fire scenario was mainly induced by spalling. However, it was also revealed that although fire-induced damage in the initial heating stage under the RWS was so close to that under the RABT, the material loss under the RWS at the later stage after 50 minutes elapsed since fire initiation was induced not by spalling but by melting.

• 한국산업보건학회지
• /
• 제22권4호
• /
• pp.265-275
• /
• 2012

Objectives: The aim of this study was to investigate the distribution patterns and exposure concentrations of biological hazards in waste handling industries. Methods: We selected 3 recyclable waste sorting plants(RWS), 2 food recycling plants(FR), 1 landfill area(LA) and 1 waste incineration plant(WI). Total airborne bacteria and fungi were measured with single stage impactor and gelatin filters. Endotoxin and glucan were measured with polycarbonate filters in total and respirable dust. Results: The geometric mean of airborne bacterial concentration was the highest in FR($3,273CFU/m^3$), followed by LA, RWS, and WI as 1,334, 934, and $860CFU/m^3$. The fungal concentrations were 6,031, 5,052, 3,307, and $713CFU/m^3$ in RWS, WI, FR, and LA, respectively. By process, WI pit showed the highest concentrations of bacteria, fungi, and endotoxin, followed by inside of bulldozer in LA. The indoor to outdoor ratios of bacteria, fungi, endotoxin and glucan were 2.3, 4.0, 2.3, and 5.0 in RWS, 29.5, 4.9, 7.6, and 5.0 in FR, 5.3, 8.7, 26.8, and 9.5 in WI, respectively. Conclusions: We found that biological hazards, specifically bacteria in FR, fungi in RWS and endotoxin in WI pit and bulldozer at LA, should be controlled to prevent worker's respiratory diseases.

• 경영정보학연구
• /
• 제25권2호
• /
• pp.163-180
• /
• 2023

본 연구는 TOE(Technology-Organization-Environment) 모델을 기반으로 원격근무 솔루션(RWS)의 기술적, 조직적, 환경적 측면을 고려해 위드 코로나 시대 이용자들의 지속사용 의도를 설명할 수 있는 연구 모형을 제안하였다. 연구 모형 및 가설 검증을 위해 국내 원격근무 솔루션 사용자를 대상으로 온라인 설문을 실시하였고 부분최소자승법(Partial Least Square, PLS)을 이용해 411개 수집 데이터를 분석하였다. 분석 결과, 기능성과 보안성은 생산성 향상과 만족도에 모두 유의한 양의 상관관계가 있음이 밝혀졌다. 또한 조직 준비성은 생산성 향상에 긍정적인 영향을 끼치나 만족도에는 영향을 주지 못하는 것으로 드러났다. 정부지원은 원격근무 솔루션의 지속사용의도에 긍정적인 영향을 미치는 것이 확인되었으나 건강에 대한 우려와 지속사용의도와의 상관관계는 유의하지 않은 것으로 나타났다. 마지막으로 생산성 향상과 만족도, 지속사용의도 간의 상관관계들은 모두 유의한 것으로 확인되어 총 11개 가설 중 9개 가설이 지지되었다.

• 한국레이저가공학회:학술대회논문집
• /
• 한국레이저가공학회 2005년도 추계학술발표대회 논문집
• /
• pp.7-10
• /
• 2005

Nowadays, most automotives companies are making use of laser welding in car body assembly shop. But even though laser welding is better than resistance spot welding in many points, its application has been limited to special technology for manufacturing. The paper introduces in the field of remote welding system(RWS) to improve the process efficiency of laser welding. Positioning time of RWS between welding stitches are dramatically reduced to zero. It is a kind of solutions to generalize laser welding in mass production.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
• /
• pp.195-196
• /
• 2009

본 연구에서는 터널별 표준시간-온도곡선에 따른 내부온도 특성을 평가하고자 수치해석을 실시하였다. 수치해석은 Hydro Carbon, Hydro Carbon Modified, RABT 및 RWS 표준시간-온도곡선에 따랐다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
• /
• pp.477-480
• /
• 2008

터널의 경우 타구조물에 비해 화재빈도가 상대적으로 높지는 않으나, 밀폐된 공간이라는 특성상 5분이내 1000도 이상으로 급격한 온도상승이 발생할 수 있으므로, 화재발생시 대형인명피해 및 화재 후 막대한 보수/보강비용이 파생된다. 이에 본 연구에서는 선진외국의 터널화재 시나리오를 준용하여 화재강도(ISO, MHC, RWS)에 따른 콘크리트 PC패널라이닝의 내부 전열특성 규명하였으며, 열손상 범위를 도출하기 위해서 ITA 기준을 적용하여 평가하였다. 연구결과 ISO화재조건에서는 30mm, MHC에서는 50mm, RWS에서는 100mm의 화재손상범위가 도출되었으며, 폭렬깊이는 RWS에서 30mm가 발생하는 것으로 나타났다. PC패널이 지보재의 역할을 할 경우엔 최소100mm깊이의 콘크리트 화재손상범위에 대한 내화성능확보방안이 적용되어야 하며, 비 지보재일 경우 PC패널라이닝의 두께를 100mm이상 확보하여야 한다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제16권3호
• /
• pp.380-383
• /
• 2003

The gas dilution technique was used to evaluate the possibility of estimating the volume of gaseous phase in the rumen from its composition in sheep given rice whole crop silage (RWS) or dent corn silage (DCS) at a level of maintenance (M) or 2 M, and in the course of fasting. The rumen gas composition was determined at 2 and 7.5 h after morning feeding. Nitrogen gas was injected by using an airtight syringe into the rumen immediately after collecting the rumen gas sample as a control. Then rumen gas samples were collected at 5, 10, 20, 40 and 60 min. after injection. Dry-matter intakes were $42g/kg^{0.75}$ and $57g/kg^{0.75}$ for DCS, and $36g/kg^{0.75}$ and $59g/kg^{0.75}$ for RWS, at 1 M and 2 M levels, respectively. Animals ingested both silages about 20% less than expected at 2 M level. The rumen gas composition did not differ significantly between 2 h and 7.5 h after feeding except for $N_2$. Content of $CO_2$ in gas composition was significantly higher at 2 M level than at 1 M (p<0.05) for both RWS and DCS, whereas $CH_4$ showed no significant difference between feeding levels. At both feeding levels, $CO_2$ showed a higher (p<0.05) percentage in DCS than RWS. A dilution technique by using $N_2$ injection is not appropriate for the determination of gas production in vivo, unless the rate of rumen gas turnover is considered. Changes in composition at fasting indicate that the rumen fermentation may reach the lowest level after 72 h fasting for sheep given silage as their sole diet.

• Journal of Welding and Joining
• /
• 제28권5호
• /
• pp.75-79
• /
• 2010

The Remote welding system(RWS) using $CO_2$ laser equipment has focusable distance of laser beam longer than 800 mm from workpiece and can deflect the laser beam by the scanner mirrors very rapidly. In the case of normal welding system based on robot, there is a limit to move the shortest path in short time and this causes interference between robot and workpiece. On the other hand, RWS is the optimized equipment to get big merits with advanced sequence of welding and short cycle time. However, there is still a pending task such as the control of plasma in the welding process of thick sheets therefore, it requires high power laser beam because of the absence of assist gas equipment in itself. In this study, high-tensile steel plates were overlap welded with $CO_2$ RWS for the production of car body and the influence of penetration depth according to the existence of assist gas was analyzed. Excellent tensile strength with enough width of molten zone independent to penetration depth was observed under welding condition with 3.6 kW laser power and 2.8 m/min welding speed without assist gas. Finally, the proto-type automotive parts were produced by applying the deduced optimal welding condition.