• Korean Journal of Organic Agriculture
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• v.9 no.1
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• pp.1-16
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• 2001

With increasing global concern that intensively synthetic-chemical based farming systems accelerated the decline in environmental quality, the sustainability of modem agriculture became the subject of great concern. It is well known that the movement of Community Supported Agriculture(CSA) has been contributed significantly to the development of organic agriculture in USA and Japan. It was supposed that CSA could be one of the best way to promote the movement of organic agriculture since there is little reliability on the organically grown food by consumer. In this paper it was focussed to study the movement of CSA in USA and Europe in order to provide an idea for establishment and movement of CSA in Korea to support the organic agriculture. In a CSA system, the farmer grows food for a group of shareholders who pledge to buy a portion of the farm's crop that season. This arrangement gives growers up-front cash to finance their operation and higher prices for produce, since the middleman has been eliminated. For most shareholder for CSA saving money is a secondary consideration, but fresh safe products and environmentally sound farming system. People become shareholder of CSA since they expect an organic farming which can ; \circled1protect the environment, minimize pollution, promote health, \circled2replenish and maintain long-term soil fertility by providing optimal conditions for soil biological activity, \circled3maintain diversity within the farming system and its surroundings and protect plant and wildlife habit, \circled4recycle materials and resources to the greatest extent possible within the farm and its surrounding community, \circled5maintain the integrity of organic food and processed products through each step of the process from planting to consumption, \circled6develop and adopt new technologies with consideration for their long range social and ecological impact. In all CSAs, the farmer develops a crop plan and a budget, which details costs for a growing season, including fair wages for the farmers. Experienced Information on increasing shareholder retention, the future of CSA, and getting started such as ideas for ongoing marketing, printed materials that set realistic expectations, working members, production, pick-up and delivery, setting prices, and receiving feedback were also briefly introduced.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.15 no.1
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• pp.243-260
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• 2004

This study investigated whether academic library user education contributes to promote users' information literacy. 39 students of Duksung Women's University participated voluntarily for this experiment. A test questions set about locating specific library materials was delivered to participating students, who were to find right answers for each test question. Their answers about test questions were measured in terms of success rate, time used to solve each problem. Self evaluation scores were also collected before and after giving them user education. Academic library user education significantly contributed participating students' ability to locate academic library materials through a library user interface. After receiving user education students were able to solve more successfully test questions, use less time for each question, and evaluate themselves more highly in terms of information utilizing ability. The effectiveness of the academic library user education was lasted for about 8 weeks after the education they received.

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.187-196
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• 2012

Recently, for the purpose of constructing artificial ecosystem, the public aquarium and experimental mesocosm systems are receiving attention. To design and establish an aquarium and mesocosm system, there is need of several materials for simulating the environment, such as sediments, rocks, and plants. Expecially for sessile mollusks, there must be proper materials to which sessile invertebrates can adhere. Nowadays, many aquariums and mesocosm systems are using dead coral skeletons for sessile mollusks. This study was proceeded to have data on the effect of dead coral skeletons on water qualities with the experiment on the environmental factors. For this purpose, I made glass tank for experiment, chose two types of dead coral skeletons imported from the Indonesia and observed the change of water qualities and decomposition efficiency of TAN (total ammonia-nitrogen), nitrite ($NO_2{^-}$) and nitrate ($NO_3{^-}$). As a result, the lager the surface area was, the more TAN, nitrite and nitrate decomposition rate increased. In addition, coral skeletons covered with crustose algae and bacteria in the tank showed faster TAN, nitrite and nitrate removal rate and stabilization. Accordingly, this experiment suggested that dead coral skeletons could be used as a sub filter for the closed system as well as an adhering plate.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1049-1055
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• 2012

The fiber mat catalytic burner that uses infrared radiative heat obtained by flameless catalytic combustion was manufactured and tested to investigate its combustion characteristics. About 9 to 17% of combustion heat was released by sensible heat during the premixed catalytic combustion depend on combustion condition. To find out radiation intensity with distance between catalytic burner and sample, the equation that calculate the receiving surface of radiative energy under the fiber mat catalytic burner was driven. This equation was well correlated with the drying rate of melamine. The drying experiments were carried out to the melamine, wood chip and agricultural pallet by using the fiber mat catalytic burner and the energy efficiency was calculated from drying rate of them. The energy efficiency of the fiber mat catalytic burner reaches to 79% in maximum for drying of the wood chip.

• Journal of the Korean Electrochemical Society
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• v.21 no.1
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• pp.6-11
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• 2018

For the high performance of the secondary battery to satisfy the demands in electronic and energy industries, it is necessary to develop more safe, environmentally friendly and economical electrode. Recently, lithium-sulfur batteries are receiving attention as next-generation secondary cells in terms of its remarkable theoretical capacity, energy density and environmental characteristics. However, they have not yet overcome a fading phenomenon due to the dissolving of the polysulfide. In this study, we intend to fabricate a battery using sulfur, a higher energy density than the other bipolar materials, as an improved secondary cell electrode material. The aim of the study is to improve battery performance with an optimal ratio of the cathode components; such as sulfur of active material and Super P of an electronic conductor.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.7
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• pp.1026-1033
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• 2009

Fine ceramics have high strength, excellent wear resistance, chemical stability and high strength at high temperature and are receiving attention in various fields such as construction, engineering, aerospace and marine science. Finish machining process is required to obtain precise ceramics components because sintering process necessary for obtaining high strength and high quality ceramics reduces the dimensions of components and precision of shape. But high strength and brittleness of ceramics materials cause difficulty in processing. So a process for obtaining wanted dimensions is studying using high temperature which makes ceramics softened and thermal affected recently. Laser beam is a very useful optical device for these kinds of processes. Laser process such as laser cutting, laser machining, laser heat treatment and laser-assisted machining(LAM) is researching to manufacture practical ceramics components using intense laser source which can cause local softening and damage of workpiece. In this paper, microstructural and mechanical properties of silicon nitride heated are studied as a basic study for researching of ceramics process by laser beam. The surface variation of HIP and SSN-silicon nitride was analyzed with SEM and EDS. A processing at $1,300^{\circ}C$ or above causes N element to combine into $N_2$ gas and the gas busts from surface. These phenomena make bloat, craters and heat defects on the surface of silicon nitride. Also, oxygen content is largely increased to oxidize the surface and it causes changing of phases and reducing of hardness of surface.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.2
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• pp.156-164
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• 2003

STS316L had been used as the structural material for energy environmental facilities, because austenite stainless steels like 316L have superior mechanical properties of which toughness, ductility, corrosion resistant and etc. However, those welded structures are receiving severe damage due to increasing of the aged degradation. Most studies until now have been carried out against fatigue behaviors of weldments, and were not well studied on nondestructive evaluation methods. In this study, the fatigue crack propagation behavior of STS316L weldment usually used for vessels of the nuclear power plant was investigated. Also, the degradation characteristics of 316L stainless steel weldments were evaluated by the ultrasonic parameter such as ultrasonic velocity, attenuation factor and time-frequency analysis. The results of this study can be used as a basic data for the prediction of the fatigue crack life of weldments structures without disjointing or stopping service of structures in service.

• The Journal of Advanced Prosthodontics
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• v.12 no.4
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• pp.218-224
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• 2020

PURPOSE. The objectives of this study were to evaluate the fracture strength and fracture patterns of provisional crowns fabricated from different materials and techniques after receiving stress from a simulated oral condition. MATERIALS AND METHODS. A monomethacrylate-based resin (Unifast Trad) and a bis-acryl-based (Protemp 4) resin were used to fabricate provisional crowns using conventional direct technique. A milled monomethacrylate resin (Brylic Solid) and a 3D-printed bis-acrylate resin (Freeprint Temp) were chosen to fabricate provisional crowns using the CAD/CAM process. All cemented provisional crowns (n=10/group) were subjected to thermal cycling (5,000 cycles at 5°-55℃) and cyclic occlusal load (100 N at 4 Hz for 100,000 cycles). Maximum force at fracture was tested using a universal testing machine. RESULTS. Maximum force at fracture (mean ± SD, N) of each group was 657.87 ± 82.84 for Unifast Trad, 1125.94 ± 168.07 for Protemp4, 953.60 ± 58.88 for Brylic Solid, and 1004.19 ± 122.18 for Freeprint Temp. One-way ANOVA with Tamhane post hoc test showed that the fracture strength of Unifast Trad was statistically significantly lower than others (P<.01). No statistically significant difference was noted among other groups. For failure pattern analysis, Unifast Trad and Brylic Solid showed less damage than Protemp 4 and Freeprint Temp groups. CONCLUSION. Provisional crowns fabricated using the CAD/CAM process and the conventionally fabricated bis-acryl resins exhibited significant higher fracture strength compared to conventionally fabricated monomethacrylate resins after the aging regimen. Therefore, CAD/CAM milling and 3D printing of provisional restorations may be good alternatives for long term provisionalization.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.5
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• pp.121-126
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• 2020

In many parts of the world, climate warming has caused tremendous environmental disasters to repeat every year. Overuse of fossil fuels, the main source of energy, has affected the global environment, destroying the global ecosystem and depleting resources. To overcome this, efforts to reduce carbon emissions through the development of renewable energy are being actively studied at home and abroad. Already, new technologies are being reported abroad to reduce carbon emissions. Zero Energy House is a model that reduces low carbon emissions and energy use due to the use of high-density materials for high-heated materials, and can live in real life by receiving the minimum required energy through renewable energy. Although the government is trying to apply this in Korea, it is difficult to become common because of the lack of economic feasibility. The purpose of this study is to study models that can zero carbon emissions, which are eco-friendly elements, secure construction economy of zero energy house by using ventilation system, heat exchanger and energy storage system for public use, and attach automation system to window opening/closing to maintain indoor temperature.

• Korean Journal of Community Nutrition
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• v.16 no.1
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• pp.98-112
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• 2011

This study aimed to suggest a 1300 scale of a middle school foodservice facility floor plan which was compliant to the principle of HACCP, as well as ensuring food and work safety, and the flow of personnel and food materials. which consisted of 46 nutrition teachers and 6 experts, responded with a questionnaire on the relationship of functional area and space. Using their opinions, key principles for the design of the facility were single direction movement of food materials, customers and workers; minimization of the cross-contamination through the separation of functional space; and securement of customer-focused efficiency; staff-centered convenience and efficiency; and work and food safety. After the completion of an adjacency diagram, bubble diagram and program statement, the functional areas of a 1300 scale middle school food-service facility were allocated as follows: $9.9\;m^2$ for the receiving area, $56.1\;m^2$ for the pre-preparation area, $10.5\;m^2$ for the food storage area, $6.0\;m^2$ for the supplies storage area, $97.8\;m^2$ for the cooking area, $33.6\;m^2$ for the service area, $52.5\;m^2$ for dish washing area, cafeteria $410.5\;m^2$, $4.5\;m^2$ for the front room, for a total of $725.8\;m^2$. Expert groups have pointed to limitations within this model as there are no windows in the office for the influx of fresh outside air and a need for the straight line installation of steam-jacket and frying kettles on the sides of windows. This study can be useful as the guidelines for estimating the investment cost of the facility and placing the placement of functional areas and equipment in the renovation of the facility. It can be also useful data for a methodology of foodservice facility design.