• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.649-656
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• 2019

Flux cored arc welding (FCAW), which is used widely in many fields, such as shipyards, bridge structures, construction machinery, and plant industry, is an alternative to shielded metal arc welding (SMAW). FCAW is used largely in the welding of carbon and alloy steel because it can be welded in all poses and obtain excellent quality in the field under a range of working conditions. In this study, the mechanical properties of welded parts were analyzed after different welding of SS400 and SM490A using FCAW. The following conclusions were drawn. The tensile test results satisfied the KS standard tensile strength in the range of 400~510 N/mm2 in all welding positions. The bending test confirmed that most of the specimens did not show surface breakage or other defects during bending and exhibited sufficient toughness, even after plastic deformation. The hardness test results were lower than the standard value of 350 Hv of KS B 0893. Similar to the hardness test, were greater than the KS reference value. The macro test revealed no internal flaws, non-metallic inclusions, bubbles or impurities on the entire cross section of the weld, and there were no concerns regarding lamination.

• Journal of Korean Academy of Nursing
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• v.25 no.4
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• pp.653-667
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• 1995

Post - operative wound infections have been a serious problem in nursing care in the operating room and appear to be strongly related to the infection occurring during the performance of operation. The purpose of this study is to identify patterns in duration of surgical hand scrub (SHS), to evaluate the method of SHS and to examine the rate of glove perforation. Subjects for this study include 244 doctors and 169 nurses working in the operative theatre of a hospital in Seoul area. Test samples and related data were collected from this medical facility between April 1, through 15, and July 1, through 5, 1995 by the author and a staff member working in the operating room. For the study, data on the SHS of doctors and nurses were obtained at the time of operation and multiple batches of surgical gloves worn by the operating doctors were collected after each operation. The duration of SHS was measured with a stop watch and the method of SHS was evaluated according to Scoring Hand Scrub Criteria (SHS Criteria) and expressed as SHS scores. For the analysis of the data, t-test was used to compare the differences in the duration and the SHS scores of doctors and nurses, and Pearson's correlation coefficient was used to examine the relationship between the SHS duration and the SHS scores. The results of the study are summarized as follows. 1) The mean time spent in each SHS was 167 seconds in nurses, and 127 seconds in doctors. The data comparing nurses and doctors indicated that there were significant differences in Our ation of SH S between these two groups (t=5.58, p=.000). 2) The mean time spent in the first SHS was 145 seconds and that in the End SHS, 135 seconds, and there was not a significant difference in the duration of the SHS between doctors and nurses (t=1.44, P=.156). 3) The mean time spent in the SHS by OS (Orthopaedic surgery) doctors was 162 seconds, 150 seconds by NS(Neurologic surgery), 121 seconds by GS(General surgery), 94 seconds by OPH(Opthalmology) and DS(Dental surgery), 82 seconds by URO(Urology), 78 seconds by PS(Plastic surgery) and 40 seconds by ENT(Ear, Nose & Throat) These also showed a significant difference in the duration of the SHS among the medical specialities (t=4.8, P=.0001). 4) The average SHS score of the nurses was 15.2, while that of doctors was 13.1. The statistical analysis showed that t-value was 3.66, p was. 000. This indicates that the nurses actually clean their hands more thoroughly than the doctors do. 5) The average SHS score of NS doctors was 15.5, 15.3 for doctors for OPH,14.3 for OS,12.7 for GS, 12.0 for DS, 11.7 for URO, 10.1 for PS, 7.5 for ENT. Comparison of the average SHS scores from 8 specialties showed that there was a significant differences in the patterns of the SHS (F=5.08, P=.000) among medical specialties. 6) It appears that the operating personnel scrub the palms and dorsum of their hand relatively well, however, less thorough the nails and fingers. 7) The more the operating personnel spend their time in hand scrubbing, the more correctly they clean their hands(r=.6427, P<.001). 8) The overall frequencies of perforation in all post-operative gloves tested was 38 out of 389 gloves (10.3%). The perforation rate for PS was 13%, 12.1% for GS,8.8% for 05, and 3.3% for NS.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.5
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• pp.119-126
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• 2011

The standard unit manpower and material in landscape architectural construction was consist of a standard and universal work classification. However, these constructional methods have created a number of problems in utilizing and responding on a variety of recently-developed working methods such as new constructional skills and technologies. This research decided that presenting the amendments of work classification of a standard unit manpower and material in landscape architectural construction was very important, and investigated those work classifications which required these new amendments. First of all, assessment items were selected through the literature reviews and a preliminary survey. Then, these assessment items were surveyed to the total of 60 professional landscape architecture field. The results of this study were as follows; First, the utilization level of the a standard unit manpower and material in landscape architectural construction was highest in the area of work classification of planting unit manpower and material. Second, the work classifications that needed to be added were recognized as leveling the ground construction, landscape structure construction, paving construction, water facilities construction, and outdoor facilities construction. Third, in the field of the a standard unit manpower and material in landscape architectural construction, 66.7% of the respondents replied that some amendments were necessary, and those amendments needed work classifications were identified as work classification of planting unit manpower and material was gigantic plant, topiary tree, temporary planting, exchange dead tree, etc. In the area of digging out was gigantic plant and plastic tree were recognized. The survey respondents also answered that, in keeping and management work classifications some amendments in pruning waste were necessary, and in the fields of rubble masonry work classifications some improvements were required in rubble aperture planting unit manpower and material and sodding and herbaceous sowing was a realistic lawn size unit manpower and material was needed. Based on the results explained above, this study suggests that amendments for a standard unit manpower and material in landscape architectural construction are necessary, especially in the areas of planting size and quality of work classifications unit manpower and material and in the unit manpower and material that affects the quality of lands caping constructions.

• Journal of Science of Art and Design
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• v.9
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• pp.5-24
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• 2006

Human hunted and picked to survive and a vessel was made naturally to store something being hunted and picket, which was a great invention. In modern times, society changed and development of science gave us convenience in making a vessel and various kinds of store instruments which was made of pure natural material, of new stuff, such as plastic and iron. but human became to be inclined to regress into nature because of problems of environment. We can say that the representative trend is well-being, after all this is a symptom to return to life being persued by predecessors before the science civilization was developed. Ancestors have lived with nature, adapted themselves to it. For examples they have built the house which became to be a part of nature and just like it, and studied a method of storing food to eat for four seasons, then displayed a storagehouse and storage containers everywhere of the house. Now Korean has the custody of kimchi in refrigerator at every house, but our forefathers controled a timing to eat food with studying a method of storage to put to use nature. With hot wind of well-being, Korean food is becoming to be globalized, according to this, concern about the wisdom of progenitors is growing more and more. It's an example that the world shows concern seriously about the pottery, which have stored kimchi for a long time fleshly, in globalization of kimchi. This study have three purposes, the first. checking documents about the development history of pottery which is a kind of ceramic, and then the second, through an scientific experiment, with studying characteristic of pottery being built by the wisdom of ancestors, informing the merit of pottery and necessity to the world, and futhermore, the third, working up the development of close environmental vessels putting to use the characteristic of pottery.

• Journal of Korean Public Health Nursing
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• v.1 no.1
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• pp.45-61
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• 1987

This Study was an attempt to estimate the optimum numbers of Operating Room Nursing Manpower by measuring the amount of service hours required by the patients in Operating Room in relation to the service amount actually provided by the nurses. The major concern of this study was placed on the measurement of Nursing Service Requirements by using the Operating Room (O. R) Patient Acuity System recently developed by M. M. Hart to classify the O. R. patients into four groups according to the degree of the complexity of operative procedure and some other elements which increase nursing activities in respect of patient care; Acuity IV group is the one requires nursing services most, on the other hand Acuity I requires least. nu sing The objectives of this study were as follows; 1. To analyze functions of the nursing personnel in O. R. by time unit and to estimate the average time a nurse can activate for productive functions. 2. To measure the actual amount of nursing times provided by nurses to the surgical patients. 3. To develop a patient classification system in order to measure the amount of Nursing services required by the patients. 4. To calculate an appropriate number of nursing manpower to meet the needs of the patients. In order to conduct the research both selected nurses and patients in 'S' University Hospital were Studied by utilizing the O. R. Patient Acuity System as well as the Classification Chart developed by Association of Operating Room Nurses (A. O. R. N) as a means of classifying functions of O. R. nurses. That is; Functions of the 10 selected O. R. nurses observed during the period of June 30 to July 4, 1986, whereas the amount of nursing services required by or provided to the 974 patients who had received surgeries during the period of June 9 to July 4, 1986. The results of this study were as follows; 1) The actual working hours per a nurse averaged 6.7 hours a day. 2) Each nurse's daily routine schedule consists of $71.4\%$ for Technical Functions, $16.1\%$ for Nonprodective Functions, $6.6\%$ for Assessment and Evaluation, $3.9\%$ for Overseeing and Supervision and the rest $2.0\%$ for Patient Preparation respectively. 3) Preoperative waiting time per a patient was 24.1 minutes on the average; for the first case was 10.7 minutes, whereas for the following cases was 32.0 minutes. 4) Total Operation time for the 974 patients during the period of observation for this study amounted to 2759.6 hours, weekly hour was equivalent to 689.9 hours, Whereas daily operation time averaged 130 hours. Meanwhile the average operation time per patient was 2.8 hours ; for the case of Acuity IV was 5.6 hours, 5. 1 hours for the case of Acuity III, 2.3 hours for Acuity II and 1.1 hours for Acuity I. 5) According to the O. R. Patient Acuity System, $64.5\%$ of the whole patients belonged to Acuity II, $23.7\%$ to Acuity III, 11. $3\%$ to Acuity IV and $0.7\%$ to Acuity I respectively. 6) Required amount of nursing times based on the preoperative waiting time and operation time was 7167.8 person hours, which showed that $5.5\%$ of them needed for preoperative nursing care, whereas the rest $94.5\%$ for intraoperative nursing care. In terms of the O. R. Patient Acuity System, $49.7\%$ of total nursing service requirements was needed for Acuity II patients, $27.4\%$ for Acuity III patients, $17.2\%$ for Acuity IV patients and $0.2\%$ for Acuity I patients. 7) The rate of the nursing services provided against the required nursing times was about $81.4\%$ on the average; some departments, like those of Plastic Surgery, Otolaryngology and Ophthalmology whose patients mostly belonged to Acuity II recorded hegher provision rate than average, whereas other departments of Thoracic Surgery. Neurosurgery and Orthopedic Surgery whose patients belonged to Acuity III and Acuity IV as well as Acuity II recorded lower provision rate than average. 8) Subsequently, required numbers of nursing manpower was 10.7 nurses additionally. Based on the above findings the following recommendations will be made; 1) this study recommends, develops. and adopts an accurate and realistic O. R. Patient Acuity System which can help measure the nursing service requirements objectively to elicit the rationales of allocation of nursing personnels. 2) this study proposes storongly place nurses who take the role of preoperative nursing care exclusively for the waiting patients in O. R. and shortening their waiting time by close communication between the designated O. R. and the ward.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.1-2
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• 2011

Hybrid rockets have lately attracted attention as a strong candidate of small, low cost, safe and reliable launch vehicles. A significant topic is that the first commercially sponsored space ship, SpaceShipOne vehicle chose a hybrid rocket. The main factors for the choice were safety of operation, system cost, quick turnaround, and thrust termination. In Japan, five universities including Hokkaido University and three private companies organized "Hybrid Rocket Research Group" from 1998 to 2002. Their main purpose was to downsize the cost and scale of rocket experiments. In 2002, UNISEC (University Space Engineering Consortium) and HASTIC (Hokkaido Aerospace Science and Technology Incubation Center) took over the educational and R&D rocket activities respectively and the research group dissolved. In 2008, JAXA/ISAS and eleven universities formed "Hybrid Rocket Research Working Group" as a subcommittee of the Steering Committee for Space Engineering in ISAS. Their goal is to demonstrate technical feasibility of lowcost and high frequency launches of nano/micro satellites into sun-synchronous orbits. Hybrid rockets use a combination of solid and liquid propellants. Usually the fuel is in a solid phase. A serious problem of hybrid rockets is the low regression rate of the solid fuel. In single port hybrids the low regression rate below 1 mm/s causes large L/D exceeding a hundred and small fuel loading ratio falling below 0.3. Multi-port hybrids are a typical solution to solve this problem. However, this solution is not the mainstream in Japan. Another approach is to use high regression rate fuels. For example, a fuel regression rate of 4 mm/s decreases L/D to around 10 and increases the loading ratio to around 0.75. Liquefying fuels such as paraffins are strong candidates for high regression fuels and subject of active research in Japan too. Nakagawa et al. in Tokai University employed EVA (Ethylene Vinyl Acetate) to modify viscosity of paraffin based fuels and investigated the effect of viscosity on regression rates. Wada et al. in Akita University employed LTP (Low melting ThermoPlastic) as another candidate of liquefying fuels and demonstrated high regression rates comparable to paraffin fuels. Hori et al. in JAXA/ISAS employed glycidylazide-poly(ethylene glycol) (GAP-PEG) copolymers as high regression rate fuels and modified the combustion characteristics by changing the PEG mixing ratio. Regression rate improvement by changing internal ballistics is another stream of research. The author proposed a new fuel configuration named "CAMUI" in 1998. CAMUI comes from an abbreviation of "cascaded multistage impinging-jet" meaning the distinctive flow field. A CAMUI type fuel grain consists of several cylindrical fuel blocks with two ports in axial direction. The port alignment shifts 90 degrees with each other to make jets out of ports impinge on the upstream end face of the downstream fuel block, resulting in intense heat transfer to the fuel. Yuasa et al. in Tokyo Metropolitan University employed swirling injection method and improved regression rates more than three times higher. However, regression rate distribution along the axis is not uniform due to the decay of the swirl strength. Aso et al. in Kyushu University employed multi-swirl injection to solve this problem. Combinations of swirling injection and paraffin based fuel have been tried and some results show very high regression rates exceeding ten times of conventional one. High fuel regression rates by new fuel, new internal ballistics, or combination of them require faster fuel-oxidizer mixing to maintain combustion efficiency. Nakagawa et al. succeeded to improve combustion efficiency of a paraffin-based fuel from 77% to 96% by a baffle plate. Another effective approach some researchers are trying is to use an aft-chamber to increase residence time. Better understanding of the new flow fields is necessary to reveal basic mechanisms of regression enhancement. Yuasa et al. visualized the combustion field in a swirling injection type motor. Nakagawa et al. observed boundary layer combustion of wax-based fuels. To understand detailed flow structures in swirling flow type hybrids, Sawada et al. (Tohoku Univ.), Teramoto et al. (Univ. of Tokyo), Shimada et al. (ISAS), and Tsuboi et al. (Kyushu Inst. Tech.) are trying to simulate the flow field numerically. Main challenges are turbulent reaction, stiffness due to low Mach number flow, fuel regression model, and other non-steady phenomena. Oshima et al. in Hokkaido University simulated CAMUI type flow fields and discussed correspondence relation between regression distribution of a burning surface and the vortex structure over the surface.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6C
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• pp.395-406
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• 2006

Drilled shafts are a common foundation solution for large concentrated loads. Such piles are generally constructed by drilling through softer soils into rock and the section of the shaft which is drilled through rock contributes most of the load bearing capacity. Drilled shafts derive their bearing capacity from both shaft and base resistance components. The length and diameter of the rock socket must be sufficient to carry the loads imposed on the pile safely without excessive settlements. The base resistance component can contribute significantly to the ultimate capacity of the pile. However, the shaft resistance is typically mobilized at considerably smaller pile movements than that of the base. In addition, the base response can be adversely affected by any debris that is left in the bottom of the socket. The reliability of base response therefore depends on the use of a construction and inspection technique which leaves the socket free of debris. This may be difficult and costly to achieve, particularly in deep sockets, which are often drilled under water or drilling slurry. As a consequence of these factors, shaft resistance generally dominates pile performance at working loads. The efforts to improve the prediction of drilled shaft performance are therefore primarily concerned with the complex mechanisms of shaft resistance development. The shaft resistance only is concerned in this study. The nature of the interface between the concrete pile shaft and the surrounding rock is critically important to the performance of the pile, and is heavily influenced by the construction practices. In this study, the influences of asperity characteristics such as the heights and angles, the strength characteristics and elastic constants of surrounding rock masses and the depth and length of rock socket, et. al. on the shaft resistance of drilled shafts are investigated from elasto-plastic analyses( FLAC). Through the parametric studies, among the parameters, the vertical stress on the top layer of socket, the height of asperity and cohesion and poison's ratio of rock masses are major influence factors on the unit peak shaft resistance.