• Title/Summary/Keyword: life processes

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BIOGEOCHEMICAL ACTIVITIES OF MICROORGANISMS IN MINERAL TRANSFORMATIONS: CONSEQUENCES FOR METAL AND NUTRIENT MOBILITY

  • Gadd, Geoffrey M.
    • Proceedings of the Korean Society for Applied Microbiology Conference
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    • 2002.10a
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    • pp.39-61
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    • 2002
  • Bacteria and fungi are fundamental biotic components of natural biogeochemical cycles for metals and metalloids and play important roles in dissolution, precipitation, oxidation and reduction processes. Some processes catalyzed by microorganisms also have important applications in environmental biotechnology in the areas of ore leaching and bioremediation.

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COSMOLOGY, EPISTEMOLOGY AND CHAOS

  • Unno, Wasaburo
    • Publications of The Korean Astronomical Society
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    • v.7 no.1
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    • pp.1-7
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    • 1992
  • We may consider the following three fundamental epistemological questions concerning cosmology. Can cosmology at last understand the origin of the universe? Can computers at last create? Can life be formed at last synthetically? These questions are in some sense related to the liar paradox containing the self-reference and, therefore. may not be answered by recursive processes in finite time. There are, however. various implications such that the chaos may break the trap of the self-reference paradox. In other words, Goedel's incompleteness theorem would not apply to chaos, even if the chaos can be generated by recursive processes. Internal relations among cosmology, epistemology and chaos must be investigated in greater detail.

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Condition Monitoring of Tool Wear and Breakage using Sound Pressure in Turning Processes (선삭공정에서 음압을 이용한 공구마멸 파손의 상태감시)

  • 이성일
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.6 no.3
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    • pp.36-43
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    • 1997
  • In order to make unmanned machining systems with satisfactory performances, it is necessary to incorporate appropriate condition monitoring systems in the machining workstations to provide the required intelligence of the expert. This paper deals with condition monitoring for tool wear and breakage during turning operation. Developing economic sensing and identification methods for turning processes, sound pressure measurement and digital signal processing technique are proposed. The validity of the proposed system is confirmed through the large number of cutting tests.

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Microbial Metal Transformations

  • Gadd, Geoffrey M.
    • Journal of Microbiology
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    • v.39 no.2
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    • pp.83-88
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    • 2001
  • There is considerable interest in how microbiological processes can affect the behaviour of metal contaminants in natural and engineered environments and their potential for bioremediation. The extent to which microorganisms can affect metal contaminants is dependent on the identity and chemical form of the metal and the physical and chemical nature of the contaminated site or substance. In general terms, microbial processes which solubilize metals increase their bioavailability and potential toxicity, whereas those that immobilize them reduce bioavailability. The balance between mobilization and immobilization varies depending on the metal, the organisms, their environment and physico-chemical conditions.

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Review of Safety Activity Process for Safety Enhancement of Railway Signaling System

  • Hwang, Jong-Gyu
    • International Journal of Safety
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    • v.10 no.2
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    • pp.27-31
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    • 2011
  • As safety-related regulations for signaling systems are standardized to IEC 61508 and 62425, and others at the international level, safety activities and its verification are required. And also there is need to develop technologies for safety improvement to secure safety signaling systems in terms of technologies for safety activities on each life-cycle. In this paper it is reviewed the safety activity processes and technologies each steps of proposed processes respectively for railway signaling systems.

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Studying Everyday Life of Families with Qualitative Methodology (가족의 일상생활 연구를 위한 질적방법론 고찰)

  • Yang, Sung-Eun
    • Journal of the Korean Home Economics Association
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    • v.44 no.8
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    • pp.171-179
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    • 2006
  • The purposes of the article are to explore historical contexts where everyday life is identified as the essence of family studies, and to suggest qualitative methodology which is effective to understand meanings of family everyday life. Everyday life is the integrity of the time when family members progress in a family life cycle, the space where they interact with each other, and the way how they achieve their developmental tasks. Qualitative methodology, coming from interpretive science paradigm, focuses on those processes, interactions, and meanings of family members in natural settings. Example researches are introduced to show what specific topic can be studied and how they be interpreted for exploring family everyday life. The future of studying everyday life is discussed in terms of the research topic and the methods.

Analysis of Thermal Behavior and Temperature Estimation by using an Observer in Drilling Processes (드릴링 공정의 열거동 해석과 관측기를 이용한 온도 추정법)

  • Kim, Tae-Hoon;Chung, Sung-Chong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.9
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    • pp.1499-1507
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    • 2003
  • Physical importance of cutting temperatures has long been recognized. Cutting temperatures have strongly influenced both the tool life and the metallurgical state of machined surfaces. Temperatures in drilling processes are particularly important, because chips remain in contact with the tool for a relatively long time in a hole. Tool temperatures tend to be higher in drilling processes than in other in machining processes. This paper concerns with modeling of thermal behaviors in drilling processes as well as estimation of the cutting temperature distribution based on remote temperature measurements. One- and two-dimensional estimation problems are proposed to analyze drilling temperatures. The proposed thermal models are compared with solutions of finite element methods. Observer algorithms are developed to solve inverse heat conduction problems. In order to apply the estimation of cutting temperatures, approximation methods are proposed by using the solution of the finite element method. In two-dimensional analysis, a moving heat source according to feedrate of the drilling process is regarded as a fixed heat source with respect to the drilling location. Simulation results confirm the application of the proposed methods.

A study on the Life Cycle Cost reduction of the LRT's power systems based on the advanced Systems Engineering (시스템엔지니어링 기법 적용에 따른 경량전철 전기시스템의 생명주기비용 절감에 관한 연구)

  • Choi, Won-Chan;Bae, Joon-Ho;Heo, Jae-Hun;Joo, Ji-Young
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1434-1439
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    • 2011
  • The purpose of this study is based on the optimize the system life cycle cost apply to the advanced systems engineering techniques consideration thought to the system life cycle for the power system which is the one of the major component of the light rail transit system. Generally, the systems engineering techniques apply to the LRT's power systems are not optimize the whole life cycle cost of the power systems because systems engineering management activities are concentrate in performing the key-technology oriented at the construction stage of the dedicated power systems for light rail transit. Through this study, All the stakeholders can be utilize a this advanced systems engineering techniques which is fully considered the life cycle cost through the considering in whole system life cycle (such as concept, design, operation, maintenance and dispose stage as well as construction stage) and adopted by KSX ISO/IEC 15288 system life cycle processes.

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FATIGUE LIFE PREDICTION OF RUBBER MATERIALS USING TEARING ENERGY

  • Kim, H.;Kim, H.Y.
    • International Journal of Automotive Technology
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    • v.7 no.6
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    • pp.741-747
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    • 2006
  • It has been almost impossible to predict the fatigue life in the field of rubber materials by numerical methods. One of the reasons is that there are no obvious fracture criteria and excessively various ways of mixing processes. Tearing energy is considered as a fracture criterion which can be applied to rubber compounds regardless of different types of fillers, relative to other fracture factors. Fatigue life of rubber materials can be approximately predicted based on the assumption that the latent defect caused by contaminants or voids in the matrix, imperfectly dispersed compounding ingredients, mold lubricants and surface flaws always exists. Numerical expression for the prediction of fatigue life was derived from the rate of rough cut growth region and the formulated tearing energy equation. Endurance test data for dumbbell specimens were compared with the predicted fatigue life for verification. Also, fatigue life of industrial rubber components was predicted.