• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.939-942
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• 2007

Vacuum cleaner is a close life product that can remove various dusts from our surroundings. However well vacuum cleaner clean our environments, many people are looking away from it, due to its loud noise. Its noise causes a big trouble in the usual life, for example, catch calls, TV watching and discussing etc. To reduce these inconveniences, noise reduction methods and systematic design of low noise vacuum cleaner are studied in this paper. At first, sound quality investigation is performed to get the noise level and quality that make people TV watching and catch calls available. Based on the European and domestic customer SQ survey result, sound power, peak noise level and target sound spectrum guideline are studied and introduced. As a second, precise product sound spectrums are designed into each part based on the sound quality result. Fan-motor, brush, mainbody, cyclone spectrums are decided to get the final target sound based on the contribution level. Fan-motor is the major noise source of vacuum cleaner. Specially, its peak sound, RPM peak and BPF Peak, cause the people nervous. To reduce these peak sounds, high rotating impeller and diffuser are focused due to its interaction. A lot of experimental and numerical tests, operation points are investigated and optimization of flow path area between diffusers is performed. As a bagless device, cyclones are one of the major noise sources of vacuum cleaner. To reduce its noise, previous research is used and adopted well. Brush is the most difficult part to reduce noise. Its noise sources are all comes from aero-acoustic phenomena. Numerical analysis helps the understanding of flow structure and pattern, and a lot of experimental test are performed to reduce the noise. Gaps between the carpet and brush are optimized and flow paths are re-designed to lower the noise. Reduction is performed with keeping the cleaning efficiency and handling power together and much reduction of noise is acquired. With all above parts, main-body design is studied. To do a systematic design, configuration design developments technique is introduced from airplane design and evolved with each component design. As a first configuration, fan-motor installation position is investigated and 10 configuration ideas are developed and tested. As a second step, reduced size and compressed configuration candidates are tested and evaluated by a lot of major factor. Noise, power, mass production availability, size, flow path are evaluated together. If noise reduction configuration results in other performance degrade, the noise reduction configuration is ineffective. As a third configuration, cyclones are introduced and the size is reduced one more time and fourth, fifth, sixth, seventh configuration are evolved with size and design image with noise and other performance indexes. Finally we can get a overall much noise level reduction configuration. All above investigations are adopted into vacuum cleaner design and final customer satisfaction tests in Europe are performed. 1st grade sound quality and lowest noise level of bagless vacuum cleaner are achieved.

• Korean Journal of Construction Engineering and Management
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• v.16 no.2
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• pp.65-76
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• 2015

The Clean Development Mechanism (CDM) is the multi-lateral 'cap and trade' system endorsed by the Kyoto Protocol. CDM allows developed (Annex I) countries to buy CER credits from New and Renewable (NE) projects of non-Annex countries, to meet their carbon reduction requirements. This in effect subsidizes and promotes NE projects in developing countries, ultimately reducing global greenhouse gases (GHG). To be registered as a CDM project, the project must prove 'additionality,' which depends on numerous factors including the adopted technology, baseline methodology, emission reductions, and the project's internal rate of return. This makes it difficult to determine ex ante a project's acceptance as a CDM approved project, and entails sunk costs and even project cancellation to its project stakeholders. Focusing on hydro power projects and employing UNFCCC public data, this research developed a prediction model using logistic regression and CART to determine the likelihood of approval as a CDM project. The AUC for the logistic regression and CART model was 0.7674 and 0.7231 respectively, which proves the model's prediction accuracy. More importantly, results indicate that the emission reduction amount, MW per hour, investment/Emission as crucial variables, whereas the baseline methodology and technology types were insignificant. This demonstrates that at least for hydro power projects, the specific technology is not as important as the amount of emission reductions and relatively small scale projects and investment to carbon reduction ratios.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.1
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• pp.51-59
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• 2016

Global consumption of fossil fuels continues to increase. As developing countries use fossil fuel as much as the existing fossil fuel using countries, the total amount of fossil fuel consumed has risen. The finite fossil energy depletion insecurity have become serious. In addition, fossil energy is caused by environmental pollution, economic and social problems remain in assignments that need to be addressed. Although solar power is clean and has many benefits, there are several problems in the process of installing a solar power plant. To solve these problems, floating photovoltaic plants has emerged as an alternative. This floating photovoltaic plants location analysis has not been made yet. In this study, the conditions of the floating photovoltaic plants location is analyzed with the Analytic Hierarchy Process using the terrain and climate factors. The score is assigned to the attribute information of each factor by the classification table. After multiplied by the weight the result is analyzed by visualization of the score. As the result, the score of the northen part of Gyeongsangbuk-do province is higher than the southern part of Gyeongsangbuk-do province. Especially Andongho lake in Andong City and the reservoir in Yeongyang-Gun are extracted as the optimal location. The score of the river boundary is low not the center of the river stream. It is expected that this study would be a more accurate floating solar power plant location analysis.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.3
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• pp.263-272
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• 2012

Carbon dioxide, emitted by human activities since the industrial revolution, is regarded as a major contributor of global warming. There are many efforts to mitigate climate change, and carbon dioxide capture and geological storage (CCS) is recognized as one of key technologies because it can reduce carbon dioxide emissions from large point sources such as a power station or other industrial installation. The inclusion of CCS as clean development mechanism (CDM) project activities has been considered at UNFCCC as financial incentive mechanisms for those developing countries that may wish to deploy the CCS. Although the Conference of the Parties serving as the Meeting of the Parties to the UNFCCC's Kyoto Protocol (CMP), at Cancun in December 2010, decided that CCS is eligible as CDM project activities, the issues identified in decision 2/CMP.5 should be addressed and resolved in a satisfactory manner. Major issues regarding modalities and procedure are 1) Site selection, 2) Monitoring, 3) Modeling, 4) Boundaries, 5) Seepage Measuring and Accounting, 6) Trans-Boundary Effects, 7) Accounting of Associated Project Emissions (Leakage), 8) Risk and Safety Assessment, and 9) Liability Under the CDM Scheme. The CMP, by its decision 7/CMP.6, invited Parties to submit their views to the secretariat of Subsidiary Body for Scientific and Technological Advice (SBSTA), SBSTA prepared a draft modalities and procedure by exchanging views of Parties through workshop held in Abu Dhabi, UAE (September 2011). The 7th CMP (Durban, December 2011) finally adopted the modalities and procedures for CCS as CDM project activities (CMP[2011], Decision-/CMP.7). The inclusion of CCS as CDM project activities means that CCS is officially accredited as one of $CO_2$ reducing technologies in global carbon market. Consequently, it will affect relevant technologies and industry as well as law and policy in Korea and aboard countries. This paper presents a progress made on discussion and challenges regarding the issue, and aims to suggest some considerations to policy makers in Korea in order to demonstrate and deploy the CCS project in the near future. According to the adopted modalities and procedures for CCS as CDM project activities, it is possible to implement relevant CCS projects in Non-Annex I countries, including Korea, as long as legal and regulatory frameworks are established. Though Korea enacted 'Framework Act on Low Carbon, Green Growth', the details are too inadequate to content the requirements of modalities and procedures for CCS as CDM project. Therefore, it is required not only to amend the existing laws related with capture, transport, and storage of $CO_2$ for paving the way of an prompt deployment of CCS CDM activities in Korea as a short-term approach, but also to establish the united framework as a long-term approach.

• Applied Chemistry for Engineering
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• v.17 no.2
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• pp.125-131
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• 2006

Dimethyl ether (DME) is a new clean fuel as an environmentally-benign energy resource. DME can be manufactured from various energy sources including natural gas, coal, biomass and spent plastic. In addition to its environmentally friendly properties, DME has similar characteristics to those of LPG. Therefore, it is considered as an excellent substitute fuel for LPG, fuel cells, power plant, and especially diesel and is expected to be the alternative fuel by 2010. The experimental study of the direct synthesis of DME was investigated under various conditions over a temperature range of $220{\sim}280^{\circ}C$, syngas ratio 1.2~3.0. All experiments were carried out with a hybrid catalyst, composed of a methanol synthesis catalyst ($Cu/ZnO/Al_2O_3$) and a dehydration catalyst (${\gamma}-Al_2O_3$). The observed reaction rate follows qualitatively a Langmiur-Hinshellwood model as the reaction mechanism. Such a mechanism is considered with three reactions; methanol synthesis, methanol dehydration and water gas shift reaction. From a surface reaction with dissociative adsorption of hydrogen, methanol, and water, individual reaction rate was determined.

• Korean Journal of Materials Research
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• v.22 no.2
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• pp.71-77
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• 2012

When a new bonding agent using coal ash is utilized as a substitute for cement, it has the advantages of offering a reduction in the generation of carbon dioxide and securing the initial mechanical strength such that the agent has attracted strong interest from recycling and eco-friendly construction industries. This study aims to establish the production conditions of new hardening materials using clean bottom ash and an alkali activation process to evaluate the characteristics of newly manufactured hardening materials. The alkali activator for the compression process uses a NaOH solution. This study concentrated on strength development according to the concentration of the NaOH solution, the curing temperature, and the curing time. The highest compressive strength of a compressed body appeared at 61.24MPa after curing at $60^{\circ}C$ for 28 days. This result indicates that a higher curing temperature is required to obtain a higher strength body. Also, the degree of geopolymerization was examined using a scanning electron microscope, revealing a micro-structure consisting of a glass-like matrix and crystalized grains. The microstructures generated from the activation reaction of sodium hydroxide were widely distributed in terms of the factors that exercise an effect on the compressive strength of the geopolymer hardening bodies. The Si/Al ratio of the geopolymer having the maximum strength was about 2.41.

• Journal of the Korean Solar Energy Society
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• v.32 no.6
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• pp.1-10
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• 2012

The annual energy production of Gangwon wind farm was predicted for three consecutive years of 2007, 2008 and 2009 using commercial programs, WindPRO and WindSim which are known to be used the most for wind resource prediction in the world. The predictions from the linear code, WindPRO, were compared with both the actual energy prediction presented in the CDM (Clean Development Mechanism) monitoring report of the wind farm and also the predictions from the CFD code, WindSim. The results from WindPRO were close to the actual energy productions and the errors were within 11.8% unlike the expectation. The reason for the low prediction errors was found to be due to the fact that although the wind farm is located in highly complex terrain, the terrain steepness was smaller than a critical angle($21.8^{\circ}$) in front of the wind farm in the main wind direction. Therefore no flow separation was found to occur within the wind farm. The flow separation of the main wind was found to occur mostly behind the wind farm.

• Journal of the Korean Society of School Health
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• v.8 no.2
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• pp.293-303
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• 1995

Health has occupied a position of importance in the human history, whether it be in the East or in the West, and it is a subject in which people have been constantly interested. The concept of health has changed continuously as the society has developed, industrialized and become more structured. The perception of health concept can be an esential factor which is to determine the health behaviors. This study is a descriptive inquiry done to identity high school students' perception of health and what they do as health behaviors. The subject consisted of 503 voctional high school seniors, 129 boys and 374 girls, from a school located in An-san Si, kyong-gi Do. The instruments used for this study were open-ended questionnaires and data were collected by having the students fill out the questionnaires which took 10 minutes, in their first class, April 6, 1995. The collected materials were classified and recorded on the cards according to each question using the terms which students had written. After putting statements which had common meanings together, the representative categories were labelled. The results obtained are as follows. 1. Categorizing and labelling of health concepts What high school students descripted as health concepts were classified as the absence of illness, physical comfort, strong physical strength and physique, not having a deformity, resisting power, self control mental-rest(or psychological comfort), wholesome ideas, self-control, harmony in body and in mind, maintenace of daily life, pleasant life, good friends, peaceful family life and realizing objectives. 2. Categorizing and labelling of health behaviors These were classified as preventive life, good dietary habits and regimen, maintenance of clean body, exercises, preventing obesity, rest, environmental balance or control of environment, limit one's tastes, making use of leisure, peaceful mind, sound thought and regular living habits. The result indicates that the health concepts were positive and included not only absence of illness but also harmony in body and in mind and pleasant life; health behaviors which had high frequency were good dietary habits and regimen, exercises and sound thought. It is hoped that these findings well serve as practical references for teachers when they counsel with, and provide the students with guidance programs which include health care.

• Resources Recycling
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• v.10 no.3
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• pp.14-22
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• 2001

For the recycle of coal fly ash generated from power stations, we developed an electrocyclone system which can separate unburned carbon form coal fly ash, based on the fact that coarse fly ash particles contain higher amount of unburned carbon and unburned carbon particles are charged positively, and pure ash particles are charged negatively on contacting each other. Additionally, guide vanes were installed in the cyclone to control the cut size. Two types of electrode, stick and grid type, were designed to investigate the effect of electrode type. Results show that by introducing an electric field inside the cyclone, the yield increases by 5 to 15e1o. But the content of unburned carbon in the clean ash does not change significantly.

• Journal of the Korean Ceramic Society
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• v.42 no.9 s.280
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• pp.618-623
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• 2005

HTGR (High Temperature Gas-Cooled Reactor) is highlighted to next generation power plant for producing the clean hydrogen gas. In this study, the spherical $UO_2$ kernel via $UO_3$ gel particles was prepared by the sol-gel process. Raw material of slightly Acid Deficient Uranyl Nitrate (ADUN) solution, which has pH = 1.10 and $[NO_3]/[U]$ mole ratio = 1.93, was obtained from dissolution of $U_3O_8$ powder with conc.-$HNO_3$. The surface of these spherical $UO_3$ gel particles, which was prepared from the broth solution, consisted of 1 M-uranium, 1 M-HMTA, and urea, were covered with the fine crystallite aggregates, and these particles were so hard that crushed well. But the other $UO_3$ gel particles prepared with the broth solution, consisted of 2 M-uranium, 2 M-HMTA, and urea, have soft surface characteristics and an amorphous phase. This type of $UO_3$ gel particles is some chance of doing possibility of high density from the compaction. The amorphous $UO_3$ gel particles was converted to $U_3O_8$ and then $UO_2$ by calcination at $600^{\circ}C\;in\;4\%\;-\;H_2\;+\;N2$ atmosphere.