• 한국안전학회지
• /
• 제37권3호
• /
• pp.1-8
• /
• 2022

Workplace accidents are common while working at elevations. Thus, various safety measures such as safety handrails and horizontal safety nets are implemented to prevent falls. The minimum safety measure is the lifeline installation. However, because its standards have not been clearly established, it is often misused, resulting in inappropriate knot methods that increase the chance of accidents while working at elevations. Therefore, clarifying the appropriate usage methods or criteria for the various lifelines is required in the field. This study proposed an appropriate installation method by experimentally and numerically evaluating the change in strength according to the fixed knot lifeline method. In addition, three knot methods were specified for each material. The results obtained are expected to contribute to lessening falls through the establishment of lifeline installation standards and the development of appropriate parts.

• Nuclear Engineering and Technology
• /
• 제55권9호
• /
• pp.3493-3505
• /
• 2023

Reactor containment buildings serve as the last barrier to prevent radioactive leakage due to accidents and their safety is crucial in overpressurization conditions. Thus, the Regulatory Guide (RG) 1.216 has mentioned the global strain as one of failure criteria in the free-field for cylindrical prestressed concrete containment vessels (PCCV) subject to internal pressure. However, there is a limit that RG 1.216 shows the free-field without the specific locations of failure criteria and also the global strain corresponding to only azimuth 135° has been mentioned in NUREG/CR-6685, regardless of the elevations of the structure. Therefore, in order to reevaluate the failure criteria of the 1:4 scaled PCCV, the high fidelity simulation model based on the experimental test was significantly validated in this study, and it was interesting to find that the experimental and numerical result was very close to each other. In addition, for the consideration of the material uncertainties, the Latin hypercube method was used as a statistical approach. Consequently, it was revealed that the radial displacements of various azimuth area such as 120°, 135°, 150°, 180° and 210° at elevations 4680 mm and 6,200 mm can represent as the global deformation at the free-field, obtained from the statistical approach.

• The Korean Journal of Physiology and Pharmacology
• /
• 제3권4호
• /
• pp.415-425
• /
• 1999

$[K^+]_o$ can be increased under a variety of conditions including subarachnoid hemorrhage. The increase of $[K^+]_o$ in the range of $5{\sim}15$ mM may affect tensions of blood vessels and cause relaxation of agonist-induced precontracted vascular smooth muscle $(K^+-induced$ relaxation). In this study, effect of the increase in extracellular $K^+$ concentration on the agonist-induced contractions of various arteries including resistant arteries of rabbit was examined, using home-made Mulvany-type myograph. Extracellular $K^+$ was increased in three different ways; from initial 1 to 3 mM, from initial 3 to 6 mM, or from initial 6 to 12 mM. In superior mesenteric arteries, the relaxation induced by extracellular $K^+$ elevation from initial 6 to 12 mM was the most prominent among the relaxations induced by the elevations in three different ways. In cerebral arteries, the most prominent relaxation was produced by the elevation of extracellular $K^+$ from initial 1 to 3 mM and a slight relaxation was provoked by the elevation from initial 6 to 12 mM. In superior mesenteric arteries, $K^+-induced$ relaxation by the elevation from initial 6 to 12 mM was blocked by $Ba^{2+}\;(30\;{\mu}M)$ and the relaxation by the elevation from 1 to 3 mM or from 3 to 6 mM was not blocked by $Ba^{2+}.$ In cerebral arteries, however, $K^+-induced$ relaxation by the elevation from initial 3 to 6 mM was blocked by $Ba^{2+},$ whereas the relaxation by the elevation from 1 to 3 mM was not blocked by $Ba^{2+}.$ Ouabain inhibited all of the relaxations induced by the extracellular $K^+$ elevations in three different ways. In cerebral arteries, when extracellular $K^+$ was increased to 14 mM with 2 or 3 mM increments, almost complete relaxation was induced at 1 or 3 mM of initial $K^+$ concentration and slight relaxation occurred at 6 mM. TEA did not inhibit $Ba^{2+}-sensitive$ relaxation at all and NMMA or endothelial removal did not inhibit $K^+-induced$ relaxation. Most conduit arteries such as aorta, carotid artery, and renal artery were not relaxed by the elevation of extracellular $K^+.$ Among conduit arteries, trunk of superior mesenteric artery and basilar artery were relaxed by the elevations of $[K^+]_o.$ These data suggest that $K^+-induced$ relaxation has two independent components, $Ba^{2+}-sensitive$ and $Ba^{2+}-insensitive$ one and there are different mechanisms for $K^+-induced$ relaxation in various arteries.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제30권5호
• /
• pp.457-464
• /
• 2008

Purpose: The aim of this study was to evaluate the clinical results of implants which were installed with maxillary sinus elevation by using lateral window technique. Materials and methods: We performed the maxillary sinus elevation by lateral window technique to 87 patients who visited Dept. of Oral & Maxillofacial Surgery, Chonnam National University Hospital from January, 2003 to January, 2007. When the residual bone height was from 3 mm to 7 mm, the sinus elevation and simultaneous implant installation was mostly performed. When the residual bone height was less than 3 mm, the sinus elevation was performed and the delayed implant installation was done after 5 or 6 months. No artificial membranes were used for coverage of the lateral bony window site and freeze dried fibrin sealant was applied to the grafted bone. The mean follow-up period was 28.5 months (ranged from 10 months to 48 months) Results: 1. Unilateral sinus elevations were performed in 51 patients and bilateral sinus elevations were performed in 36 patients. And the total number of sinus elevation procedure was 123 cases. 2. The sinus elevation and simultaneous implant installation was performed in 89 sinuses and 249 implants were installed. The sinus elevation and delayed implant installation was performed in 44 sinuses and 141 implants were installed. The total number of implants were 390 in 133 sinuses. The average healing period after sinus elevations was 6.1 months in delayed implant installation. 3. Only autogenous bone, autogenous bone mixing with allografts or autogenous bone mixing with xenografts were used as graft materials. 4. The average period from first surgery to second surgery was about 7.2 months. 5. Some patients complications, such as perforation of sinus membrane, swelling, infection and exposure of cover screw. Two implants were removed in the infected sinus. 6. The survival rate of implants with maxillary sinus elevation by lateral window technique was 99.5% and the success rate of implants was 95.1%. Conclusions: These results indicated that the implants which were installed with maxillary sinus elevation by lateral window technique showed high survival and success rates.

• 대한토목학회논문집
• /
• 제28권3B호
• /
• pp.271-281
• /
• 2008

본 연구는 도시지역의 토지이용 및 건축 측면에서 방어침수위 설정방법으로 과거 침수실적을 적용하는 방법, 인근하천의 기준홍수위를 연장하는 방법, 강우빈도별 시나리오에 의한 내수침수 모의방법(하천 및 소유역 임계지속기간) 등 네 가지 방법을 검토하고, 서울시 중랑천 연변의 장안배수분구를 사례로 적용하여 결과를 비교 분석한다. 분석 결과, 인접하천의 기준홍수위를 단순연장하는 방법을 제외하고는 다소의 차이는 있으나 대체로 유사한 결과를 보였다. 침수원인이 내수침수에 의한 지역일 경우에는 방어침수위로 침수실적자료를 이용한 과거 최대침수위를 적용하거나, 인근하천의 계획홍수량을 발생시키는 강우사상에 대한 내수침수 모의결과를 적용하는 것이 합리적일 것으로 판단된다. 다만, 과거 침수실적자료의 구축이 미비하고 내수침수가 주된 침수원인인 지역에서 인근하천의 기준홍수위를 적용할 경우에는 주의보수위나 경보수위를 적용하는 것이 합리적인 것으로 판단되며, 당해지역의 주된 침수원인이 외수범람(하천월류, 제방붕괴 등)에 의한 지역일 경우에는 인근하천의 계획홍수위를 적용하는 합리적인 것으로 판단된다. 한편 각각의 방법에 의해 산정된 방어침수위의 타당성 여부를 판단하기 위해 해당 방어침수위 이하 건축물의 거실용도 사용을 제한하는 경우에 대해 경제성분석을 실시한 결과, 모든 방법들이 경제적 타당성이 없는 것으로 나타난 한편, 소유역의 임계지속기간의 내수침수를 모의한 경우 비교적 B/C Ratio가 비교적 높게 나타났다.

• 한국주거학회논문집
• /
• 제8권3호
• /
• pp.17-27
• /
• 1997

This thesis is concerned with a study of spatial characteristics of Korean traditional architecture in visual perception. This study, therefore has been made of principles of visual perception. range of visual perception in architectural environment, spatial characteristics of Korean traditional architecture, and example case studies are exhibited. The architectural compositional principles of parts selected in process of study could be selected to facilitate comparison with the perceptual psychology. The result of this study can be used to construct Korean architectural plans. elevations. form and spatial and order pertinent to human understandings and existances on the priority of wholeness and the relationship of parts to visual perception.

• 한국농림기상학회:학술대회논문집
• /
• 한국농림기상학회 2001년도 춘계 학술발표논문집
• /
• pp.135-138
• /
• 2001

The study area, the Kwangnung Experimental Forest (KEF) region is located at the west-central portion of the Korean peninsula (Figure 1), and covers 2, 240ha. Elevations range about from 90m to 600m, and the highest peak is Mt. Jukyeopsan (600.6m). Kwangnung Natural Reserve Forest area is about 1, 200ha, which has been protected from human activities for a long time.(omitted)

• 대한조선학회논문집
• /
• 제41권3호
• /
• pp.22-27
• /
• 2004

Waveheight attenuation efficiencies of floating breakwaters in water of finite depth for a VLFS are studied numerically in accordance with the two body radiation-diffraction problem. Four different forms of the breaker are tested with a solid VLFS. The radiation-diffraction wave elevations between the breakwater and the VLFS are predicted directly instead of the far-field transmission-reflection coefficients of the breakwater.

• 동굴
• /
• 제5호
• /
• pp.96-106
• /
• 1997

The reduction of cave survey data is an essentially straightforward but repetitive mathematical task which can be carried out to advantage using virtually any type of computer from a programmable calculator upwards. The obvious benefits are speed and accuracy in reducing and adjusting the raw data to obtain the x,y,z coordinates (eastings, northings and elevations) of the surveyed points. Additionally, depending on the functionality of the software (program) and power of the hardware (computer), the user may be able to build up a data base of surveys, plot out on paper scaled plans and elecations of the cave and possibly even see a three-dimensional model of the cave, in perspective or some other projection, as an aid to understanding the spatial relationships of cave passages.(omitted)

• 한국해양공학회지
• /
• 제26권3호
• /
• pp.33-38
• /
• 2012

The aim of this experimental study was to analyze the effect of the shape parameters and chamber pressure of a land-based oscillating water column (OWC) in regular incident waves. The magnitude of the free surface elevations inside the chamber was measured in a two-dimensional wave tank for various chamber skirt drafts and bottom slope angles. The surface elevations were also measured under both open chamber and partially open chamber conditions. From these measurements, the optimum shape of the OWC device could be predicted for the maximum wave energy conversion efficiency. It was found that the resonance frequency of the OWC system associated with incident waves moved toward the long wave region with increments of the draft of the chamber skirt and bottom slope. The behavior of the free surface elevation inside the chamber was also found to be dependent on the chamber pressure.