• Title/Summary/Keyword: conservation integral

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An Environmental Impact Statement for Wetlands Conservation (습지보전을 위한 환경영향평가제도)

  • Lee, Sang-Don
    • Journal of Wetlands Research
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    • v.2 no.1
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    • pp.1-9
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    • 2000
  • The purpose of Environmental Impact Statement (EIS) is an integral component of decisions on proposed plans, projects, and actions. Adapted from the National Environmental Policy Act(NEPA, 1969) environmental impact statement in Korea has aimed to analyse and prepare the mitigation in the process of big scale development and major industrial planning. During the past 19 years EIS has played the central role for the environmental issues in the process of economic development. Nevertheless EIS act needs some modification in the system as well as in the contents of evaluation process. EIS should be served as decision-making process by assessing environmental issues in the beginning stage of proposed actions. Other consideration was suggested to make EIS system better used for environment conservation.

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Similarity evaluation of the pump simulation loop in STELLA-2 for conservation of mechanical sodium pump characteristics

  • Jung Yoon ;Jewhan Lee ;Jaehyuk Eoh;Hyungmo Kim ;Dong Eok Kim
    • Nuclear Engineering and Technology
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    • v.55 no.1
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    • pp.353-363
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    • 2023
  • The STELLA-2 is a large-scale sodium thermal-hydraulic integral effect test facility and supports the development of PGSFR. The facility adopted Pump Simulation Loop System (PSLS) concept for the mechanical sodium pump in the reference reactor to control and to measure the primary sodium flow. Since the component (mechanical pump) is replaced by the loop, it is very important to evaluate the similarity between the pump and the loop. In this paper, to simulate the characteristic of the mechanical sodium pump, the pressure loss along the various options of the loop was evaluated and the comprehensive validity of each design options was analyzed. Using the similarity criteria based on the Richardson number and Euler number conservation, the PSLS design was finalized and the result was within the acceptable error range. Finally, the result of this study was used for construction of the overall facility, STELLA-2.

Insight Into the Crystallinity of Chinese Ancient Silk by Synchrotron Radiation-Based and Conventional X-ray Diffraction Methods

  • Gong, Decai;Zhang, Xiaoning;Gong, Yuxuan
    • Journal of Conservation Science
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    • v.36 no.1
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    • pp.1-14
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    • 2020
  • This study investigates the crystallinity distribution of ancient silk. Owing to the inherent multi-hierarchical structure of silk protein and the complicated structural changes that occur due to various burial environments, it is challenging but worthwhile to study ancient silk ageing behavior, which is based on the fact that ageing begins with a single fiber and then spreads to a whole fabric. Crystallinity was one of the most effective indicators found to reveal the ageing status of silk. Therefore, a synchrotron radiation-based X-ray diffraction(SR-XRD) method was employed to study the crystallinity distribution of single fibers of ancient silk unearthed from seven archaeological sites in China from historical periods including the warring states, Han dynasty, Song dynasty, and Ming dynasty. In comparison, the conventional X-ray diffraction method, which uses large amounts of samples, was also performed to determine the integral crystallinity of ancient silk. Thermal stability experiments by thermogravimetry(TG) as well as morphology observations by scanning electron microscopy(SEM) and optical microscopy(OM) all confirmed the deterioration of ancient silk. Moreover, the ageing mechanism of ancient silk was proposed with the assistance of an artificial ageing study. The results confirmed the effectiveness of SR-XRD as an ageing indicator, revealing the crystallinity distribution. This research could provide motivation to determine the deterioration status of ancient silk, and would also aid in explaining the fragility of ancient silk due to ageing.

Application of L Integral to Interface Crack Problems (계면균열 문제에 대한 L적분의 응용)

  • 박재학;엄윤용
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.10 no.1
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    • pp.34-42
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    • 1986
  • An interface of a circular arc formed by two isotropic, homogeneous elastic materials is investigated. It is shown that L integral satisfies the conservation law for the interface if it is perfectly bonded, in frictionless contact or separated such as in a crack with the origin of the coordinate system being located at the center of the circular arc. The property of path independence of the L integral is applied to an interfacial crack problem, to obtain the stress intensity factors, where the interfacial crack is located along the arc of the circular inclusion embedded in infinite matrix. It is assumed here that the contact zone exist as in the model proposed by Comninou, thus removing the overlapping of the materials along the interface. Another example is shown for case of a circular interfacial crack in the matrix of finite size, where the stress intensity factors are determined by computing a value of the L integral numerically along the path far from the crack tip.

The Performance of Capacity Modulation and MIMO Control for System Heat Pump (시스템 히트펌프의 용량조절 및 다변수 제어 특성에 관한 연구)

  • Song, In-Sik;Joo, Young-Ju;Chung, Hyun-Joon;Kang, Hoon;Kim, Yong-Chan;Choi, Jong-Min
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.364-369
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    • 2007
  • A system heat pump provides the benefits of comfort, energy conservation and easy maintenance. Recently, the system heat pump has been employed in small and medium-sized buildings. However, the performance data and control algorithm for system heat pump are limited in literature due to complicated system parameters and operating conditions. In the present study, the performance of a system heat pump with two indoor unit is measured by varying indoor loads, EEV opening, and compressor speed. In addition, the integral optimum regulator which includes MIMO control algorithm is proposed. The capacity modulation and optimum capacity for each indoor unit can be adjusted by utilizing the EEVs opening and compressor speed. The proposed scheme shows appropriate control performance at test conditions.

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Self-pressurization analysis of the natural circulation integral nuclear reactor using a new dynamic model

  • Pilehvar, Ali Farsoon;Esteki, Mohammad Hossein;Hedayat, Afshin;Ansarifar, Gholam Reza
    • Nuclear Engineering and Technology
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    • v.50 no.5
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    • pp.654-664
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    • 2018
  • Self-pressurization analysis of the natural circulation integral nuclear reactor through a new dynamic model is studied. Unlike conventional pressurized water reactors, this reactor type controls the system pressure using saturated coolant water in the steam dome at the top of the pressure vessel. Self-pressurization model is developed based on conservation of mass, volume, and energy by predicting the condensation that occurs in the steam dome and the flashing inside the chimney using the partial differential equation. A simple but functional model is adopted for the steam generator. The obtained results indicate that the variable measurement is consistent with design data and that this new model is able to predict the dynamics of the reactor in different situations. It is revealed that flashing and condensation power are in direct relation with the stability of the system pressure, without which pressure convergence cannot be established.

Use of Water Buffalo for Environmental Conservation of Waterland - Review -

  • Georgoudis, A.G.;Papanastasis, V.P.;Boyazoglu, J.G.
    • Asian-Australasian Journal of Animal Sciences
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    • v.12 no.8
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    • pp.1324-1331
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    • 1999
  • The aim of this paper is to propose the preservation of buffaloes not only as productive livestock, but also as a part of the biodiversity of wetlands and especially of the Greek wetlands. The water buffalo used to be an integral part of the biodiversity of many Greek wetland ecosystems, enriched their landscape, and provided invaluable services and products to the rural people and to the economy in general. Its total population before the 1950s was over 100,000 animals. Presently, it is found only in four wetland sites in Macedonia and Thrace and in the estuaries of Rivers Gallikos and Axios, with a total population of a few hundred animals. These wetlands are Ramsar Sites. Even this small population is threatened with immediate extinction because of the rapidly changing rural socio-economic conditions and the expansion of cultivated fields into wet meadows. Farmers and consumers are rapidly losing contact with this mammal and its products. This species possesses minimum requirements for treatment and is characterized by the ability of utilizing roughage of variable nutritional value. These factors are promising to render buffalo breeding a valuable branch of the Greek livestock sector, which can also contribute to the maintenance of the wetlands.

Suggestion of the Five Laws for Integral Studies (통합학문 5대 법칙의 제안)

  • Kim, Deok-Jin
    • Plant Journal
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    • v.14 no.1
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    • pp.34-41
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    • 2018
  • Current study is the era of fusion, and future study is the era of integration. The prerequisite of study integration is that all studies must be equal to each other, and only laws derived from natural laws can achieve the equivalence of integration. We suggest that the ability to make change is defined as energy. All things change, the change necessarily has directionality, therefore change and directionality apply equally to all studies. The zeroth law of integral studies is the law of existence, the first law is the law of change conservation, the second law is the law of increasing non-available change, the third law is the law of the guidelines, and the fourth law is the law of fusion. The above laws are very similar to the law of thermodynamics. The ultimate aim of the five integral laws is the realization of a community in which natural, human, and AI individuals cooperate and develop each other on the earth.

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Theoretical Analysis of Steady State Low Current Arcs in Dual Flow Nozzles

  • Song, K.D.;Shin, Y.J.;Lee, H.S.;Kim, K.S.
    • Proceedings of the KIEE Conference
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    • 1992.07b
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    • pp.952-957
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    • 1992
  • When the circuit-breaker switches off, an electric arc is established between the contacts. It is very important to understand the arc characteristics for the design of a circuit breaker. This article describes the theoretical analysis of the arc characteristics by means of energy integral method when convection dominated low current arcs are produced in the dual-airflow nozzle of a model interrupter. In order to investigate the arc radius, the average electric field strength and the arc voltage, the arc column is divided into two regions, and then the energy conservation equation is applied to the arc in each region together with the axial cold flow mass flux function, steady-state mass balance equation and Ohm's law. The results show good agreements with those of other researchers.

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Approximate Solution of Absorption Process in an Air-Cooled Vertical Plate Absorber (공냉식 수직평판형 흡수기의 흡수과정에 대한 근사해법)

  • Jeong, E.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.6 no.4
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    • pp.453-462
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    • 1994
  • An unsteady quasi one-dimensional model of momentum, heat and mass transfer in a falling film of a vertical plate absorber which is cooled by air was developed using the integral method. Energy conservation of the absorber wall is considered in the model. The model can predict absorption rate, film thickness and mean velocity as well as concentration and temperature profiles. Predictions of steady state temperature and concentration profiles for LiBr/water system for constant wall temperature condition are in good agreement with the two-dimensional finite difference method solutions. Effects of operating conditions, such as convective heat transfer coefficient between the cooling air and the absorber wall, cooling air temperature and film thickness at inlet, on absorption rate of water vapor into LiBr/water solution were shown.

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