• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.743-751
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• 2016

It is critical to effectively change the measures of prevention from the breakdown maintenance proceeding an apartment housing maintenance task scope. It is necessary that systematization be performed for a series of tasks, such as facility inspection, diagnosis and replacement. In addition, it is preceded by establishing a standardization for maintenance work scope. Therefore, this study examined the problems related to public rental housing maintenance work scope to manage it more systematically. In addition, the study suggests a work process section for facility repairs, long term replacement and general maintenance using one on one interviews with experts to classify the occupants, management office and head office. This study's standard work system is expected to provide fairness and transparency in addition to improving the productivity in public rental housing maintenance via an efficiency promotion plan. In addition, it is used as the basic reference for developing a system of public rental housing maintenance costs and diagnosis actions. Finally, it is necessary to create improvements that provide a more objective work system standardization throughout the analysis of the productivity data according to the work flow and the review of the occupants, management office and head office in the future applications of the pilot site.

• Journal of Korean Home Economics Education Association
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• v.1 no.1
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• pp.53-62
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• 1989

Cooking practice is keenly related to not only the betterment of family health but to the improvement of dietary life. Cooking is a kind of practical skill and one is skill in it by repeated practice. The aim of cooking practice in school is to fix cooking method practically and scientifically, to acquire cooking skill. To achieve this aim there are many unrecognized or unsolved problems in the first-line schools. The problems and efficient ways of cooking practice in the middle and high school are as follows； 1. The aim of cooking practice： It should be first of all remembered that the practice is so practical that the knowledge and skill of cooking should be related to the future domestic life. Second, the practice should be able to serve the communal and national life by scientifying and improving life. 2. The content of the practice： First, it should be so arranged step by step that the content of each year should not be repeated. Second, the ratio of Korean cooking practice should be increased and the material of the practice should be chosen in consideration of the peculiarity of the community, seasons and economical problems so that it may be applied to the very day life. Third, to improve dietary life, the practice should be a way of the simplification of dietary life, of the nutritional efficiency. Forth, for the betterment of physical condition of the family the practice should involve balanced dietary plans and dietary therapy. 3. Teaching method： First, the practice should be scientific and comprehensive in consideration of not only cooking skills but also knowledge of nutrition. Second, micro-class system should be adopted, and practice labor should be allotted each student to develop cooperative attitude and the sense of responsibility. Third, in addition to the practice conducted in a body, comparative cooking, applicable cooking and experimental ability and the content of the text. Fourth, teachers should let the students examine and find problems by bringing them to a focus on the basis of theory. 4. Administration method： First, the practice schedule should be planned that a class has practices at least more than twice a semester. Second, two hours of class should be continued without cessation after beforehand survey and theory study. Third, facilities and utensils for practice should be enlarged. That is, cooking practice rooms, tools, utensils should be prepared. Fourth, enough cost of practice should be secured. The above mentioned points show the present situation and problems with which cooking practice teaching is confronted. In order to normalize cooking practice teaching, the first-line schools should give the above mentioned problems their careful consideration and improve the present situation so that efficient, creative, practical cooking practice will be possible.

• Journal of Energy Engineering
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• v.29 no.2
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• pp.1-9
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• 2020

In recent days, fuel cell has received attention from the world as an alternative power source to hydrocarbon used in automobile engines. With the industrial advances of fuel cell, There have been a lot of researches actively conducted to find a way of generating hydrogen. Among many hydrogen production methods, Solid Oxide Electrolysis Cell(SOEC) is not only a basic way but also environment-friendly method to produce hydrogen gas. Solid Oxide Electrolysis Cell has lower electrical energy demands and high thermal efficiency since it is possible to operate under high temperature and high pressure conditions. For these reasons, experimental researches as well as studies on numerical modeling for Solid Oxide Electrolysis Cell have been under way. However, studies on numerical modeling are relatively less enough than experimental accomplishments and have limited performance prediction, which mostly is considered as a result from inadequate effects of electrochemical properties by temperature and pressure. In this study, various experimental studies of commercial Membrane Electrode Assembly (MEA) composed of Ni-YSZ (40wt%, Ni-60 wt% YSZ)/8-YSZ (TOSOH, TZ8Y)/LSM (La_0.9Sr_0.1MnO₃) was utilized for improving effectiveness of SOEC model. After numerically analyzing effects of electrochemical properties according to operating temperature, causing the largest deviation between experiments and simulation are that Charge Transfer Coefficient (CTC), exchange current density, diffusion coefficient, electrical conductivity in SOEC. Analyzing temperature effect on parameter used in overpotential model is conducted for modeling of SOEC. cross-validation method is adopted for application of various MEA and evaluating feasibility of model. As a result, the study confirm that the numerical model of SOEC based on structured process of effectiveness evaluation makes performance prediction better.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.698-705
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• 2017

Environmental impact of a mobile phone charger containing recycled plastic was quantified using LCA and the environmental benefits from the use of recycled and virgin plastic were compared. The assessment considers potential environmental impacts across the whole life cycle of the charger including; pre-manufacturing; manufacturing; distribution; product use; and end-of-life stages and quantified six environmental impact categories; Abiotic depletion; Acidification; Eutrophication; Global warming; Ozone layer depletion; and Photochemical oxidants creation. The study showed that the environmental impacts of the use stage accounted for 94.4% and 70% in the resource depletion and global warming impact categories, respectively, and the environmental impacts of the pre - manufacturing stage accounted for more than 98% in the other impact categories. The main cause of the environmental impacts in the use stage was electricity consumed by the charger. The main cause in the pre-manufacturing stage was PBA (Printed Board Assembly) and external case manufacturing. In order to quantify the environmental benefits of recycled PC (Polycarbonate) in the exterior case, the environmental impacts of 1 kg production of recycled PC and virgin PC were evaluated. The environmental impact on the abiotic depletion of the recycled PC is estimated to be 30% compared to the virgin PC, and the impacts on the other impact categories of the recycled PC were less than 5% of the virgin plastic. Sensitivity analysis was performed for 12 items including site data and assumptions made. The sensitivity of each item was less than 10%. The results of this study confirm that designing compact and light PBA, improving charging efficiency, and use of recycled plastic are important design factors to reduce the environmental impact of a charger.

• Journal of Korea Port Economic Association
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• v.28 no.1
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• pp.25-52
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• 2012

In order to solve the current problems and inefficiencies within the Port Authorities(PA) in Korea, this study introduces the concept of the integration of PA and analyses the intention of integration. This study is based on analysing the surveys participated by the members of PA. The surveys consist of six main factors which could influence the intention of integration of PA; contribution, autonomy, strategic factor, financial factor, marketing factor and environmental factor. The two main implications from this study can be categorised as follows. First, this study identifies the structural problems such as regional self-centredness of PA, obscurity of organisations' roles and their rights, limitations on diversification of business and restrictions within PA. Second, this study extensively discusses the option of improving the inefficiency whilst maintaining the current system or to switch to the integration of PA. In addition, it has been found that individual PA recognise the little need for integration. Since the results show that the strategic, financial, marketing and environmental factors would cause both significant and little significant impacts, it would be too haste to decide on a conclusion. However, it is possible to say that the rapid integration of PA can neither improve the efficiency nor improve the characteristics of each region. Therefore, the significance of integration of PA must be further discussed from many different perspectives. The results of this research will serve as a basic literature for further studies on the integration of PA in Korea. Moreover, the problems that have been identified and analysed in this study will contribute to establishing the strategy for further development of PA in Korea.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.6
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• pp.1056-1062
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• 2008

To evaluate the effect of irradiation on restructured pork jerky containing paprika and Japanese apricot extracts, the quality of protein was determined in vitro based on the formation of trypsin indigestible substrate inhibitor (TIS) and the computed protein efficiency ratio (C-PER) as determined based on the protein digestibility and amino acid analysis. In addition, we compared the effects of electron beam irradiation to those of gamma irradiation. Approximately 3% of the moisture content of pork jerky was reduced in response to irradiation with 3kGy administered using an electron beam however, no additional reduction was observed in samples that were subjected to higher doses of irradiation. In addition, there were no notable differences in the crude protein and fat content of pork jerky samples that were subjected to irradiation, regardless of dose. Furthermore, the total amino acids profiles did not change in response to electron beam irradiation. However, the in vitro protein digestibility increased by 7% in response to 3kGy of electron beam irradiation and 5kGy of gamma irradiation, but no significant changes in digestibility were not observed in response to treatment with higher doses. TIS quantified as trypsin inhibitors were formed in response to irradiation using the electron beam (3kGy) and gamma rays (5kGy), although there was a slight reduction in the production of TIS inhibitors in samples irradiated with higher doses. Moreover, only samples irradiated with 10kGy (electron beam and gamma ray) showed higher TBA values than those of the control samples. Finally, the C-PERs $(2.50{\sim}2.60)$ were greater in all of the irradiated pork jerky samples than in the control samples (2.22). Taken together, these results suggest that electron beam irradiation and the incorporation of extracts (paprika and Japanese apricot) may be useful methods of improving the nutritional quality of pork jerky.

• Journal of Ginseng Research
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• v.44 no.4
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• pp.627-636
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• 2020

Background: Cultivation of medicinal crops, which synthesize hundreds of substances for curative functions, was focused on the synthesis of secondary metabolites rather than biomass accumulation. Nutrition is an important restrict factor for plant growth and secondary metabolites, but little attention has been given to the plasticity of nutrient uptake and secondary metabolites synthesis response to soil nitrogen (N) change. Methods: Two year-field experiments of Sanqi (Panax notoginseng), which can synthesize a high level of saponin in cells, were conducted to study the effects of N application on the temporal dynamics of biomass, nutrient absorption, root architecture and the relationships between these parameters and saponin synthesis. Results: Increasing N fertilizer rates could improve the dry matter yields and nutrient absorption ability through increasing the maximum daily growth (or nutrient uptake) rate. Under suitable N level (225 kg/ha N), Sanqi restricted the root length and surface and enhanced the root diameter and N uptake rate per root length (NURI) to promote nutrient absorption, but the opposite status of Sanqi root architecture and NURI was found when soil N was deficient. Furthermore, increasing N rates could promote the accumulation of saponin in roots through improving the NURI, which showed a significant positive relationship with the content of saponin in the taproots. Conclusion: Appropriate N fertilizer rates could optimize both root architecture and nutrient uptake efficiency, then promote both the accumulation of dry matter and the synthesis of saponins.

• Journal of the Korean Solar Energy Society
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• v.34 no.1
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• pp.98-104
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• 2014

Photovoltaic (PV) cell is considered as one of the finest ways to utilize the solar power. A study of improving solar cell's efficiency is important because the lifetime of solar cell is determined by photovoltaic module technology. Therefore, oxidation (and/or corrosion) of solder materials will be one of the primary yield and long-term reliability risk factor. Recently, the development of lead-free solder alloy has been done actively about lead-free solder alloys of the thermodynamic and mechanical properties. However, the oxidation behavior have rarely been investigated In this study, the oxidations of 60 wt% Sn-40 wt% Pb, 62 wt% Sn-36 wt% Pb -2 wt% Ag, 50wt% Sn-48 wt% Bi-2 wt% Ag alloys for the interconnect ribbon after exposure in atmosphere at $100^{\circ}C$ for several times were investigated. The wettability of 62 wt% Sn-36 wt% Pb-2 wt% Ag and 50 wt% Sn-48 wt% Bi-2 wt% Ag solders was also studied to compare with that of 60 wt% Sn-40 wt% Pb alloy. The results howed that the zero cross time and the wetting time of 50 wt% Sn-48 wt% Bi-2 wt% Ag solder were better than other two samples. The surface of tested samples was analyzed by XPS. The XPS result showed that in all samples, SnO grew first and then the mixture of SnO and $SnO_2$ was detected. $SnO_2$ grew predominantly for the long time aging. Moreover XPS depth profile analysis has found surface enrichment of tin oxide.

• Journal of the Korean Solar Energy Society
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• v.36 no.3
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• pp.53-61
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• 2016

Solar assisted heat pump system uses solar thermal energy as a heat source of evaporator of heat pump. So, COP can be enhanced as well as collector efficiency. For improving performance of this system, some research about hybrid solar collector that has fin-and-tube heat exchanger has been conducted. This collector can get a thermal energy from ambient air for liquid heating, so heated liquid can be used as a heat source of evaporator in heat pump even the solar radiation is not enough. In this study, numerical analysis was conducted for confirming heat gain of liquid according to fin height and pitch of fin-and-tube heat exchanger in collector. As a result, higher heat gain was obtained on lower fin height and narrow fin pitch, but the pressure drop also increased with increment of heat gain. Thus the JF factor considering both heat transfer enhancement and pressure drop was investigated and the maximum value was shown when the fin height and pitch were 40mm and 45mm. So it is considered that this installation condition has a highest heat transfer improvement when comparing with pressure drop. However heat gain of liquid at this condition was less than the other installation conditions of fin pitch on same height. Then, after establishing a proper minimum heat gain of liquid, actual production and experiment of collector will be conducted with fin height and pitch showing maximum JF factor and satisfying selected minimum heat gain of liquid on the basis of results of this study.

• Fire Science and Engineering
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• v.29 no.2
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• pp.79-83
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• 2015

The fire accident is a representative type of disaster that can largely impact on business. Therefore, precautionary measures and rapid initial response is very important when a disaster occurs. The storage of porous combustibles is inevitable in coal yard, plywood processing industry, and others that are currently operating. Initial fire fighting of fire and identifying the ignition point in such a porous combustible storage space are so difficult that if the initial response is failed, being led to deep-seated fire, surface fire is likely to result in secondary damage. In addition, deep-seated fire can cause personal injuries and property damage due to a large amount of toxic gases and reignition. Therefore damage reduction measures is required around the storage space to handle a porous flammable. Improving the penetration performance of the concentration of the surfactant is carried out as underlying study, which is about an deep-seated fire extinguishing efficiency augmentation when using wetting agents. The porous materials used in the experiments is radiata pine wood flour, which occupies more than 75% of the domestic wood market. Fire fighting water is selected as Butyl Di Glycol (BDG), which is being used for infiltration extinguishing agent, and the experiment was carried out by producing a standard solution. The experiment was carried out on the basis of the Deep-Seated Fire Test of NFPA 18. The amount of watering, porous material to the internal amount of penetration, and runoff measurement out of the porous material was conducted. According to experimental results, as the surface tension is reduced, the surfactant concentration macroscopic penetration rate decreases, but infiltration to a porous material is shown to have growth characteristics.