• KIEAE Journal
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• v.10 no.5
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• pp.123-129
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• 2010

This study aimed at analyzing the trend of carbon dioxide emission for direct and indirect areas by using inter industry relations table between 2000, 2003 and 2005 in the key building materials and components. Results of this study are as follows; First, the material and components for this study was selected in 20 industries of products such as sand, gravel, cement, concrete articles, rebar, and steel bar. Second, among the 20 selected key building materials, the group with the highest carbon-dioxide emission was shown in ready-mixed concrete, concrete articles, and primary aluminum goods. Third, as a result of analyzing the changes to the units of carbon dioxide emission according to passage of time, the number of items which is changed in such as sustained increase or decrease over time was insignificant in carbon-emission change trend.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.237.1-237.1
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• 2010

Recent developments such as concern over global warming, depletion of fossil fuels and increase in energy demands by the increasing world population has eventually lead to mass production of electricity using renewable sources. Ocean contains energy in form of thermal energy and mechanical energy: thermal energy from solar radiation and mechanical energy from the waves and tides. The current paper looks at generating power using waves. The primary objective of the present study is to maximize the primary energy conversion (first stage conversion) of the base model by making some design changes. The model entire consisted of a numerical wave tank and the turbine section. The turbine section had three components; front guide nozzle, augmentation channel and the rear chamber. The augmentation channel further consisted of a front nozzle, rear nozzle and an internal fluid region representing the turbine housing. Different front guide nozzle configuration and rear chamber design were studied. As mentioned, a numerical wave tank was utilized to generate waves of desired properties and later the turbine section was integrated. The waves in the numerical wave tank were generated by a piston type wave maker which was located at the wave tank inlet. The inlet which was modeled as a plate wall which moved sinusoidally with the general function, $x=asin{\omega}t$. In addition to primary energy conversion, observation of flow characteristics, pressure and the velocity in the augmentation channel, rear chamber as well as the front guide nozzle are presented in the paper. The analysis was performed using the commercial code of the ANSYS-CFX. The base model recorded water power of 29.9 W. After making the changes, the best model obtained water power of 37.1 W which represents an increase of approximately 24% in water power and primary energy conversion.

• Journal of The Korean Association of Information Education
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• v.10 no.2
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• pp.241-248
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• 2006

Recently, as the importance of the information communication ethics education has increased, the research about new instructional method or contents have been progressed actively. On the other hand, due to the advance of e-learning technology, instead of teacher-centered instruction, the development of learning contents and learning method for satisfying students' requirements is proceeded actively. In this paper, in order to increase the learning effect for information communication ethics education for primary school students, we propose a new way to design an instruction which considers the characteristics and the requirements of students. We decompose instructional design features into 4 components such as goal, model, contents, and media, and then we pose questionnaire to the 5th grade students of a primary school. After that, we analyze data by using the conjoint analysis. Based on the result of the conjoint analysis, we give instructions to two classes in order to compare the learning achievement of the two classes. Finally, by evaluating the students and analyzing their satisfaction levels, we diagnose the effectiveness of the proposed method.

• Nuclear Engineering and Technology
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• v.47 no.4
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• pp.434-442
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• 2015

The advanced passive pressurized water reactor (PWR) is being constructed in China and the passive residual heat removal (PRHR) system was designed to remove the decay heat. During accident scenarios with increase of heat removal from the primary coolant system, the actuation of the PRHR will enhance the cooldown of the primary coolant system. There is a risk of power excursion during the cooldown of the primary coolant system. Therefore, it is necessary to analyze the thermal hydraulic behavior of the reactor coolant system (RCS) at this condition. The advanced passive PWR model, including major components in the RCS, is built by SCDAP/RELAP5 code. The thermal hydraulic behavior of the core is studied for two typical accident sequences with PRHR actuation to investigate the core cooling capability with conservative assumptions, a main steam line break (MSLB) event and inadvertent opening of a steam generator (SG) safety valve event. The results show that the core is ultimately shut down by the boric acid solution delivered by Core Makeup Tank (CMT) injections. The effects of CMT boric acid concentration and the activation delay time on accident consequences are analyzed for MSLB, which shows that there is no consequential damage to the fuel or reactor coolant system in the selected conditions.

• Analytical Science and Technology
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• v.30 no.5
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• pp.287-294
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• 2017

As the demand for natural gas increases with industrial development, the supply of natural gas is expected to become unstable with a shortage of imported natural gas. It is hence necessary to meet this demand by introducing and developing various types of natural gas, such as pipeline natural gas (PNG) and substituted natural gas (SNG), in addition to liquefied natural gas (LNG). The components included in PNG as well as their concentrations must be measured accurately, and a standard gas should be developed to accurately measure hydrocarbons ($C_6-C_{10}$), which are trace components included in natural gas. The components in the primary standard gas mixtures (PSMs) developed in the present study were hexane, heptane, octane, nonane, and decane with concentrations of $10-30{\mu}mol/mol$ with methane as the balance gas. Standard hydrocarbon ($C_6-C_{10}$) gas mixtures were prepared in aluminum cylinders by a gravimetric method with traceability following ISO 6142 with raw material gases, for which the purity of each component was analyzed completely. The prepared standard gas mixtures were analyzed by to evaluate the preparation consistency between the standard gas mixtures, the adsorbability of the cylinders, the variation of the stability, and the uncertainty. The results showed that aluminum cylinders have little adsorptive loss on their internal surfaces with excellent long-term stability. The developed standard gas mixture, containing hexane, heptane, octane, nonane, and decane with concentrations of $10-30{\mu}mol/mol$, showed an uncertainty in a range of 0.79 % - 1.63 %.

• Journal of Power Electronics
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• v.3 no.3
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• pp.145-150
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• 2003

Reliability, availability, and cost have been the major concerns for photovoltaic hybrid systems since their beginning as primary sources for much critical applications like communication units and repeaters. This paper descnbes the performance of two hybrid systems, photovoltaic-battery, wind-turbine coupled with the public-grid (PVBWG) hybrid system and photovoltaic-battery, wind-turbine coupled With the diesel generator (PVBWD) hybrid system The systems are sized to power a typical 300W/48V de telecommunication load continuously throughout the year Such hybrid systems consist of subsystems, which in turn consist of components Failure of anyone of these components may cause failure of the entire system. The reliability and availability basics, and estimation procedure for the two proposals are introduced also in this paper. The PVBWG and PVBWD system configurations are shown with the relevant mean-time-between-faIlure (MTBF) and failure rate (${\lambda}$) of each component. The characteristics equations of the two systems are deduced as a function of operating hours and the percentage of sun and wind availabilities per day. The system probability failure as well as the reliability is estimated based on the fault tree analysis technique. The results show that, by using standard or normal components MTBF, the PVBWG is more reliable and the time of periodic maintenance period is more than one year especially in the rich sites of both sun and wind, but PVBWD competes else Also, in the first five years from the system installation, the system is quit reliable and may not require any maintenance. The results show also, as the sun and wind are available, as the system reliable and available.

• Journal of the Korean Society for Library and Information Science
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• v.50 no.4
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• pp.97-120
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• 2016

This study is to objectively deduce components of a public library culture and define a library culture. Thus, the study gathers the opinions and the experiences of the expertise in this specific area of a library culture. Furthermore, the study takes gathered informations and dates into consideration, to derive a measurement of final components, delphi technique. Through usage of Delphi technique, it allowed selected final components to operate a comparative analysis of the elements, which then it helps to measure each element's critical importance, identify priorities of each element by using a hierarchical decision making method. The major conclusions of this study are as follows. First, the study used a two-step delphi survey which was conducted on a panel of experts (Faculty of Library and Information Science (LIS) and the librarians), deduced the components of a library culture. In the primary survey, the study found 29 components (material culture 6, non-material culture 23). In the secondary survey, it deduced 21 components (material culture 3, non-material culture 18). Second, through comparative analysis, the prioritization of the public library culture components presented in following orders, , , and . The Most weighted values of each components were, of 'data usage and its method.'; of 'core values of librarianship'; of 'library ethical consciousness.' appeared as such.

• Journal of Aerospace System Engineering
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• v.14 no.2
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• pp.44-49
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• 2020

This work is intended to develop a flapping-type vertical wind turbine system that will be applicable to diesel generators and wind turbine generator hybrid systems. In the aerodynamic design of the wind turbine blade, parametric studies were performed to determine an optimum aerodynamic configuration. After the aerodynamic design, the structural design of the blade was performed. The major structural components of the flapping-type wind turbine are the flapping blade, the connecting part, and the stopper. The primary focus of this work is the design and analysis of the connecting part. Structural tests were performed to evaluate the blade design, and the test results were compared with the results of the analysis.

• The Journal of the Korea Contents Association
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• v.20 no.4
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• pp.582-590
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• 2020

This paper aims to analyze and introduce the primary English curriculum of North Korea reformulated according to the New Educational Program. Sources for analysis are the 4th and 5th primary school English syllabus based on the New Educational Program, explanations of the New Educational Program appeared in People's Education and Kim, Jeong-Il's selected writings. The analytical sources are classified into characteristics, objectives, contents, methods and evaluation. The findings are as follows: The primary English education aims to reach to the basis of middle school English by learning English alphabets and basic English expressions. 4th graders learn basic oral English such as pronunciation, stress and intonation for the first semester and learn English alphabets and their sounds for the second semester. 5th graders learn familiar topics in English and repeatedly practice the important components of English such as pronunciation, vocabulary and grammar. The method is to maintain students' interests in English and encourage students to use classroom English. Also, structural practice is an important part of the method. Evaluation is primarily process-oriented and must motivate students to excel in English rather than fail in English.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.83-84
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• 2008

The primary water stress corrosion cracking (PWSCC) of dissimilar metal weld based on Alloy 82/182 is one of major issues in material degradation of nuclear components. It is well known that the crack initiation and growth due to PWSCC is influenced by material's susceptibility to PWSCC and distribution of welding residual stress. Therefore, modeling the welding residual stress is of interest in understanding crack formation and growth in dissimilar metal weld. Currently in Korea, a numerical round robin study is undertaken to provide guidance on the welding residual stress analysis of dissimilar metal weld. As a part of this effort, the present paper investigates distribution of welding resisual stress of a ferritic low alloy steel nozzle with dissimilar metal weld using Alloy 82/182. Two-dimensional thermo-mechanical finite element analyses are carried out to simulate multi-pass welding process on the basis of the detailed design and fabrication data. The present results are compared with those from other participants, and more works incorporating physical measurements are going to be performed to quantify the uncertainties relating to modelling assumptions.