• Korean Journal of Environmental Agriculture
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• v.2 no.2
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• pp.114-119
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• 1983

Several supplementary heating methods were investigated to find their effects on night air temperature, injury in plant, growth and yield with Hokowase strawberry(Fragaria grandiflora) under greenhouse, during early spring season in 1981 and 1982. Kerosene lamp as a supplementary heating was not suitable because of its severe injury on strawberry plants, danger of accidental fire and bad smell. Paraffine candle and electric wire heating did not injure on strawberry plant, raised the minimum air temperature in greenhouse at night, enhanced growth, flowering and harvesting time of strawberry. Paraffine candle was effective as a supplementary heating method for short period growing under greenhouse, whereas electric wire heating was suitable for long period cultivation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.81-89
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• 2018

Austenitic stainless steels have excellent corrosion resistance, durability and fire resistance. Especially, since STS304L among austenitic types is a low-carbon variation of STS304 and has excellent intergranular corrosion resistance, it can often be used under the welded condition without heat treatment after field welding. This paper investigated ultimate behaviors such as ultimate strength and weld metal fracture mechanism of STS304L fillet-welded connections with TIG(tungsten inert gas) welding through test results. Main variables of specimens are weld length and welding direction against loading. Fracture of specimens are classified into three modes(tensile fracture, shear fracture and block shear fracture). Ultimate strengths were compared according to the welding direction and weld length and TFW series with transverse fillet weld had the highest strength compared with other types(LFW series with longitudinal fillet weld and FW series with all round weld). It is known that current design specifications such as KBC 2016 and AISC2010 underestimated the strength of TFW and LFW specimens and provided unconservative estimates for FW specimens. Finally, strength equations were proposed considering material properties of STS 304L material.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.112-117
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• 2017

This study demonstrated the emission of combustion gases of medium density fibreboard (MDF)s coated with piperazinomethyl-bis-phosphonic acid (PIPEABP), methylpiperazinomethyl-bis-phosphonic acid (MPIPEABP), N,N-dimethylethylenediaminomethyl-bis-phosphonic acid (MDEDAP), or bis-(dimethylaminomethyl) phosphinic acid (DMDAP). Each MDFs were coated in three times with a brush with 15 wt% aqueous solution of the phosphorus-nitrogen acid additives. After the specimens were dried at room temperature, the emission of combustion gases was tested using a cone calorimeter (ISO 5660-1, 2). The peak smoke production rate ($SPR_{peak}$) of the specimens coated with phosphorus-nitrogen acids was 18.5 to 41.5%, which is lower than that of using the virgin plate. However, the production of peak carbon monoxide ($CO_{peak}$) was 6.7 to 24.2% higher than that of using the virgin plate. Also, the peak carbon dioxide ($CO_{2peak}$) was 4.2 to 24.4% lower than that of using virgin plate. While the peak oxygen depletion rate was much higher than the level of 15%, which can be fatal to humans and the resulting risk could thus be eliminated. Overall, the combustibility of coated specimens was partially suppressed, but showed a negative effect on the reduction of carbon monoxide.

• Journal of the Korea Concrete Institute
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• v.28 no.6
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• pp.673-683
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• 2016

In recent years, frequent terror or military attack by explosion, impact, fire accidents have occurred. Particularly, World Trade Center collapse and US Department of Defense Pentagon attack on Sept. 11 of 2001. Also, nuclear power plant incident on Mar. 11 of 2011. These attacks and incidents were raised public concerns and anxiety of potential terrorist attacks on major infrastructures and structures. Therefore, the extreme loading researches were performed of prestressed concrete (PSC) member, which widely used for nuclear containment vessel and gas tank. In this paper, to evaluate the blast resistance capacity and its protective performance of bi-directional unbonded prestressed concrete member, blast tests were carried out on $1,400{\times}1,000{\times}300mm$ for reinforced concrete (RC), prestressed concrete without rebar (PSC), prestressed concrete with rebar (PSRC) specimens. The applied blast load was generated by the detonation of 55 lbs ANFO explosive charge at 1.0 m standoff distance. The data acquisitions not only included blast waves of incident pressure, reflected pressure, and impulse, but also included displacement, acceleration, and strains at steel, concrete, PS tendon. The results can be used as basic research references for related research areas, which include protective design and blast simulation under blast loading.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.99-108
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• 2011

Almost all companies have paid much attention to the safety management ranging from maintenance to operation even at the stage of designing in order to prevent accidents, but fatal accidents continue to increase throughout the world. In particular, it is essential to systematically prevent such fatal accidents as fire, explosion or leakage of toxic gas at factories in order to not only protect the workers and neighbors but also prevent economic losses and environmental pollution. Though it is well known that accident probability is very low in NPP(Nuclear Power Plants), the reason why many researches are still being performed about the accidents is the results may be so severe. HRA is the main process to make preparation for possibility of human error in designing of the NPP. But those techniques have some problems and limitation as follows; the evaluation sensitivity of those techniques are out of date. And the evaluation of human error is not coupled with the design process. Additionally, the scope of the human error which has to be included in reliability assessment should be expanded. This work focuses on the coincidence of human error and mechanical failure for some important performance shaping factors to propose a method for improving safety effectively of the process industries. In order to apply in these purposes into the thesis, I found 63 critical Performance Shaping Factors of the eight dimensions throughout studies that I executed earlier. In this study, various analysis of opinion of specialists(Personal Factors, Training, Knowledge or Experience, Procedures and Documentation, Information, Communications, HMI, Workplace Design, Quality of Environment, Team Factors) and the guideline for construction of PSF were accomplished. The selected method was AHP which simplifies objective conclusions by maintaining consistency. This research focused on the implementation process of PSF to evaluate the process of PSF at each phase. As a result, we propose an evaluation model of PSF as a tool to find critical problem at each phase and improve on how to resolve the problems found at each phase. This evaluation model makes it possible to extraction of PSF succesfully by presenting the basis of assessment which will be used by enterprises to minimize the trial and error of construction process of PSF.

• The Journal of Sustainable Design and Educational Environment Research
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• v.17 no.2
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• pp.11-21
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• 2018

This study suggests desirable disaster safety education curriculum through analyzing the operational status of the school disaster safety management training course and demand survey of school staff. First, the problem of the disaster safety training course of the school is not connected with the lack of law and system and the school disaster safety job. Second, improvement of law and system and variety of training should be made to acquire professional knowledge. Third, it is necessary to divide curriculum into the following four categories, according to educational needs of public officials ; Educational administration officers course focused on facility safety, maintenance and disaster countermeasure. Educational officials in technical post course addressing approval and permission of school facility projects, seismic reinforcement of school building, etc. Educational supervisors course covering roles and responsibilities of the school safety supervisors in the event of disaster. Teaching staffs course focused on safety instructions for students. Fourth, it is found that lectures and experiential learning methods are the most desirable methods of teaching and learning, and the major ranks are earthquake disaster, fire, gas, typhoon, school road, and electrical safety.

• Korean Journal of Community Nutrition
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• v.16 no.6
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• pp.730-739
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• 2011

The purpose of this study was to analyze the differences between child-care facilities and kindergartens towards the need for foodservice support by Center for Child-Care Foodservice Management (CCFSM). For this study, questionnaires were sent out from August of 2008 to April of 2009 to directors of 1,478 child care facilities and 299 kindergartens in Seoul and Gyeonggi-do via postal service. A total of 267 questionnaires were usable with 203 (13.7%) of child-care facilities and 64 (21.4%) of kindergartens. Statistical data were analyzed by SPSS 15.0 for descriptive analysis and t-test. For political and administrative support, government funding for foodservice was the highest need and hiring nutritionists was significantly different by type of facility (p < 0.01). Both child-care facilities (4.29) and kindergartens (4.41) demanded the balanced menu from CCFSM. There were significant differences of "information about food material sanitation management" (p < 0.05), "hygiene safety management method according to working process" (p < 0.05), "hygiene safety management method of foodservice facilities and equipment" (p < 0.05). In education and training contents from center, "types and methods to manage foodservice facilities and equipment" for directors, "dietary education by age" for teachers, and "the rules of personal sanitation and working process" and "gas, electricity and fire prevention" for culinary workers had the highest mean score of requirements.

• Land and Housing Review
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• v.8 no.3
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• pp.189-200
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• 2017

The work breakdown structure and the precedence relations by work activity are very important because they are the basic data for estimating the construction duration in the construction work. However, there is no standard to accurately estimate the construction duration since the size of the school facilities construction is smaller than the general construction work. Therefore, some schools are unable to open in March or September and the delay of the construction duration can cause damage to the students. To solve this problem, this study developed a work breakdown structure of school facilities construction work and analyzed the precedence relations by work activities. The work breakdown structure of the school facilities construction is composed of three steps. The operations corresponding to level 1 and level 2 are as follows. (1) 2 preparatory work categories; preparation period and temporary construction. (2) 17 architectural work categories; temporary construction, foundation & pile work, reinforced concrete work, steel roof work, brick work, plaster work, tile work, stone work, waterproof construction, wood work, interior construction, floor work, metal work, roof work, windows construction, glazing work and paint construction. (3) 7 mechanic and fire work categories; outside trunk line work, plumbing work, air-conditioning equipment work, machine room work, city gas plumbing work, sanitation facilities and inspection & test working. (4) 4 civil work categories; wastewater work, drainage work, pavement work and other work. (5) 1 landscaping work categories; planting work. The work breakdown structure was derived from interviews with experts based on the milestones and detailed statements of existing school facilities. The analysis of precedence relations by school facilities work activity utilized PDM(Precedence Diagramming Method)which does not need a dummy and the relations were applied using FS(Finish to Start), FF(Finish to Finish), SS(Start to Start), SF(Start to Finish). The analysis of this study shows that if one work activity is delayed, the entire construction duration may be delayed because the majority of the works are FS relations. Therefore, it is necessary to use the Lag at the appropriate time to estimate the standard construction duration of the school facility construction. Lag is a term used only in the PDM method and it is used to define the relationship between the predecessor and the successor in creating the network milestone. And it means the delay time applied to the two work activities. The results of this study can reasonably estimate the standard construction duration of school facilities and it will contribute to the quality of the school facilities construction.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.296-303
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• 2005

The co-pyrolysis characteristics of polyvinylchloride (PVC) and acrylonitrile butadiene styrene (ABS) mixtures with various mixing ratios and effect of addition of CaO and $Cu_2O$ have been studied using thermogravimetry (TG) and gas chromatograph-mass spectrometry (GC-MS). In an isothermal decomposition conducted at $500^{\circ}C$, the yields of styrene monomers and aromatic compounds increased as the mixing ratio of ABS increased, and the yield of BTX compounds reached its maximum (16.14%) when the mixing ratios of PVC and ABS was 4:1. In an isothermal decomposition added with metal oxides, the maximum yield of liquid product was 73% when CaO [CaO/(PVC+ABS)=0.4] was added and it was 70% when $Cu_2O$ [$Cu_2O$/(PVC+ABS)=0.4] was added, respectively, where HCl contained in the gaseous product was completely removed when added with CaO [CaO/(PVC+ABS)=0.5] and $Cu_2O$ [$Cu_2O$/(PVC+ABS)=1.0]. Therefore, to obtain the highest yield of liquid product it appears to be the reaction condition: the reaction temperature of $500^{\circ}C$ and mixing ratios of CaO and $Cu_2O$ are 0.5 and 1.0, respectively.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.33-40
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• 2021

The objective of this work is to prove a possibility of void f illing through a carbonation f or the purpose of improving the quality of recycled aggregate. Carbonation can permanently immobilize CO2, which is a greenhouse gas, and thus provides additional benefit on environment. In this work, recycled fine aggregate was reacted using gaseous CO2 and supercritical CO2(scCO2) in a closed chamber, and the changes in physical properties of the recycled f ine aggregate bef ore and af ter carbonation were analyzed using the apparent density, skeletal density, pH, and FE-SEM measurements. Thereafter, a mortar specimen was prepared and a compressive strength was measured. According to the experimental results, it was found that the increase in the apparent density and the true density was higher by the reaction with scCO2, which was conducted at high temperature and high pressure compared to the reaction with gaseous CO2. In addition, the pH of the eluted water was found to have a larger initial decrease than that observed with samples from reaction by gaseous CO2. The shape and amount of calcium carbonate crystals were also found to be larger than that from gaseous CO2. The increase in compressive strength was the largest when using recycled fine aggregate reacted with scCO2. It was clear that quality improvement of recycled fine aggregate was higher with scCO2 than with gaseous CO2.