A study on the efficiency advancement for evacuation of the crews by ship structural improvement (선박 구조 개선을 통한 승무원의 피난 효율 향상을 위한 연구)
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- Journal of Advanced Marine Engineering and Technology
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- v.38 no.3
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- pp.342-348
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- 2014
Onshore great fires can normally be extinguished by firefighters using special firefighting equipment and its suitable method. However, offshore fires on the ships are to be extinguished by the crew without any supports from the onshore. Also, crews working on board are exposed to high risk of emergency evacuation due to the complicated structure arrangement of the ships and different accident types such as fire and ship collisions. As most of damage and loss of life in fire are associated with suffocation, shortening of evacuation time is an important factor to improve a survival rate. In this study, visibility in the accommodation area is analyzed by using the temperature and smoke flow which are obtained by the Fire Dynamic Simulator(FDS) as a Three-Dimensional Fire Analysis program to understand the survival rate of the crew upon the fire. The fire doors for most of ships are designed to close automatically when the fire alarm is activated. These automatic closing of the fire doors is a very effective system to delay the spread of flame and smoke flow for the unmanned spaces of the fire protected area. However, if the crew cannot escape within the estimated time, the crew inside the fire protected area will be damaged a lot. In this paper, the comparative analysis between the evacuations by using the fire door from the fire protected area and the suggested fire shielding structure in this study is carried out by the smoke flow rate and the temperature rise rate.
Rural spaces are increasingly valuable as areas for introducing renewable energy infrastructure to achieve carbon neutrality. Rural areas are the living grounds of rural residents, and the balance of conservation and development for rural areas is important for the introduction of reasonable facilities. In order to maintain a balance between development and preservation and to introduce reasonable renewable energy facilities, it is necessary to develop a current status survey and an effective survey method to utilize a space capable of introducing renewable energy facilities such as idle land and vacant houses. Therefore, this study was conducted to verify the readability using an unmanned aerial vehicle, and the main results are as follows. The detection of photovoltaic power generation facilities using unmanned aerial vehicles was effective in analyzing the location and area of photovoltaic panels located on the roofs of buildings, and it was possible to calculate the expected power generation by region through the area calculation of photovoltaic panels. The vacant house detection can be used to select an investigation target for an vacant house condition survey as it can identify damage to buildings that are expected to be empty houses, management status, and electricity supply facilities through aerial photos. It is judged that the unmanned aerial vehicle detection capability can be utilized as a method to improve the efficiency of investigation and supplement the data related to solar power generation facilities and vacant houses provided by public institutions. Although this study detected the status of solar power generation facilities and vacant houses through high-resolution aerial image analysis, as a follow-up study, automatic measurement methods using the temperature difference of solar power generation facilities and general characteristics of vacant houses that can be read from the air were investigated. If the deriving research is carried out, it is judged that it will be possible to contribute to the improvement of the accuracy of the detection result using the unmanned aerial vehicle and the expansion of the application range.
In this study, we analyzed the water temperature variability in the sea area of the Korean Peninsula in August, before and after the typhoon inflow through Typhoon Soulik, the 19th in 2018 that turned right around the Korean Peninsula and passed through the East Sea, and Typhoon Bavi, the eighth in 2020 that advanced north and passed through the Yellow Sea. The data used in this study included the water temperature data recorded in the real-time information system for aquaculture environment provided by the National Institute of Fisheries Science, wind data near the water as recorded by the automatic weather system, and water temperature data provided by the NOAA/AVHRR satellite. According to the analysis, when typhoons with different movement paths passed through the Korean Peninsula, the water temperature in the East Sea repeatedly upwelled (northern winds) and downwelled (southern winds) depending on the wind speed and direction. In particular, when Typhoon Soulik passed through the East sea, the water temperature dropped sharply by around 10 ℃. When Typhoon Bavi passed through the center of the Yellow Sea, the water temperature rose in certain observed areas of the Yellow Sea and even in certain areas of the South Sea. Warmer water flowed into cold water regions owing to the movement of Typhoon Bavi, causing water temperature to rise. The water temperature appeared to have recovered to normal. By understanding the water temperature variability in the sea area of the Korean Peninsula caused by typhoons, this research is expected to minimize the negative effects of abnormal climate on aquaculture organisms and contribute to the formulation of damage response strategies for fisheries disasters in sea areas.
Algal blooms of cyanobacteria (blue-green Algae) due to the eutrophication of rivers and lakes can cause not only the damage by its biological toxins but also the economic loss in drinking water treatment. The natural algae coagulant, a commercial product known as W.H. containing the algicidal and allelopathic material derived from oak, can control algal problems proactively through the coagulation flotation process. However, because there have been no applications of the process for pre-treatment in drinking water plants, we could find no report on the optimum injection dose of W.H.. In this study, we have conducted several sets of jar-tests while changing W.H. dose and concentration of chl-a for (1) Han-river samples and (2) subcultured cyanobacteria samples, and monitored the removal mechanisms of algae intensively. Based on these jar-test results, two linear equations with variables of chl-a and turbidity have been deduced to predict the optimal W.H. dose after the multiple regression analysis using IBM-SPSS. Also, prototypes of automatic control logic have been suggested to inject the optimal W.H. dose promptly in response to the variation of water quality.
This study was conducted to improve the insufficiency of fruit vegetable grafting system developed by National Institute of Agricultural Sciences, Rural Development Administration. When the rotary blade cut the stem of scions and rootstocks, the grafting failure at curved cutting surfaces happened. The cutting depth of a tomato seedling by a rotated cutter was calculated 0.11 mm even when the cutting arm length and the maximum stem diameter were 50 mm and 5 mm, respectively. Mathematical analysis and high-speed photography showed that there was no problem by cutting in straight the stem of scions and rootstocks. The compression test of seedling stems to design the optimal shape of gripper showed that stems were not completely restored when they were compressed above 0.8 mm and 0.6 mm in case of rootstocks and scion, respectively. This study found that the bending angle of stem of tomato seedlings at the grafting period was 10 degree on average. The optimal gripper finger was the edge finger type which could be precisely set center point by adjusting the distance between fingers. In addition, it was found that most of seedling could be grasped without damage when the finger-to-finger distances is set to 2.5 mm for scion and 3.0 mm for rootstocks and finger are coated by 1 mm-thick flexible material.
The purpose of this study was to analyze the number of visitors to the top of Seoseokdae in Mudeungsan National Park, in which visitors are concentrated, and their visiting patterns, thereby suggesting measures to manage the visitors. The number of annual visitors and the numbers of regional and seasonal visitors to Mudeungsan National Park, which affect the concentration of visits to Seoseokdae were analyzed using the data produced by an automatic digitizing device. A field study was conducted to examine the number of seasonal and periodic visitors to Seoseokdae and their visiting patterns. In 2015, the number of visitors was 2,563,651 and 83.9% of the visitors visited via the Jeungsimsa and Wonhyosa area that is near Gwangju City. This area is close to the Seoseokdae area and it is easy to hike between the areas. Therefore, there was an influx of most visitors to Seoseokdae into the Jeungsimsa and Wonhyosa area. In terms of seasonal visitors, the largest number of visitors came in the fall, followed by the summer, spring, and winter in order. However, the seasonal differences were not notable. There was no statistically significant correlation between the number of visitors and meteorological factors. This result may have been because Gwangju citizens frequently visit Mudeungsan regardless of period and weather. Visitors can get to Seoseokdae via the trails into Wonhyosa and Jangbuljae. A slightly larger number of visitors used the trail into Jangbuljae in the fall and winter, whereas a larger number of visitors used the trail into Wonhyosa in the summer. In general, there is a large influx of visitors into Jangbuljae, a strategic visiting point. However, a slightly larger number of visitors may have chosen the trail into Wonhyosa in the summer because they could hike under the shade of trees. In the summer, visitors stayed in Seoseokdae for a short time with a low level of crowdedness. On the other hand, in the fall and winter, visitors stayed in the area longer because they had lunch and rested. During the time, the number of momentary maximum visitors peaked, causing extreme crowdedness. Therefore, some visitors showed the visiting pattern of entering the grassland outside the designate zone. Because this behavior can damage the grassland on the top of Seoseokdae, which can lead to soil erosion, intensive visitor management may be necessary.
The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70
The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70