• Title/Summary/Keyword: Life stage

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The Effect of Compressive Residual Stresses on Fatigue Strength in DIN50CrV4-SAE9254 Steel (DIN50CrV4-SAE9254강의 피로강도에 미치는 압축잔류응력의 영향)

  • 박경동;정찬기
    • Journal of Ocean Engineering and Technology
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    • v.15 no.3
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    • pp.93-99
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    • 2001
  • Recently the steel parts used at automobils are required to be used under high stress more than ever before in need of the weight down. To achieve this requirement of a high strength steel, it must be necessary to decrease inclusion content and surface defect as like decarburization, surface roughness etc.. In this study, the surface conditions are measured to know the influence on fatigue properties by two cases of shot peening of two-stage shot peening and single-stage shot peening. And for this study, two kinds of spring steel (SAE 9254, DIN50CrV4) are used. This study shows the outstanding improvement of fatigue properties at the case of two-stage shot peening in the rotary bending fatigue test and this is assumed to be from (1) on low stress condition, th 1st stage shot peening is not affected by nonmetallic inclusion under metal.(2) it is possible that the 2nd stage shot peening increases the fatigue life and the high stress but that is affected by nonmetallic inclusion under metal. (3) so far beeasily DIN50CrV4 have made high stress. But, results also show fatigue failures originated at inclusion near surface, and this inclusion type is turned out to be a alumina of high hardness.

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Effect of Shot Peening on Fatigue Strength of JISG4081SUP7-DIN50CrV4 Steel (JISG4081SUP7-DIN50CrV4강의 피로강도에 미치는 쇼트피이닝의 영향)

  • 박경동;정찬기
    • Journal of Ocean Engineering and Technology
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    • v.15 no.4
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    • pp.66-72
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    • 2001
  • Recently the steel parts used at automobiles are required to be used under high stress more than ever before in need of the weight down. To achieve this requirement of a high strength steel, it must be necessary to decrease inclusion content and surface defect as like decarburization, surface roughness etc.. In this study, the surface conditions are measured to know the influence on fatigue properties by two cases of shot peening of two-stage shot peening and single-stage shot peening. And for this study, two kinds of spring steel (JISG4081SUP7, DIN 50CrV4) are used. This study shows the outstanding improvement of fatigue properties at the case of two-stage shot peening in the rotary bending fatigue test and this is assumed to be from on low stress condition, the 1st stage shot peening is not affected by nonmetallic inclusion under metal. it is possible that the 2nd stage shot peening increases the fatigue life and the high stress but that is affected by nonmetallic inclusion under metal. so far beeasily DIN50CrV4 have made high stress. But, results also show fatigue failures originated at inclusion near surface, and this inclusion type is turned out to be a alumina of high hardness.

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The Effect of Symptom Experience and Resilience on Quality of Life in Patients with Colorectal Cancers (대장암 환자의 증상경험과 극복력이 삶의 질에 미치는 효과)

  • Choi, Kyung-Sook;Park, Jung-Ae;Lee, Joo-Hyun
    • Asian Oncology Nursing
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    • v.12 no.1
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    • pp.61-68
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    • 2012
  • Purpose: This study aimed to investigate the influence of resilience and symptom experience on quality of life. Methods: Seventy five patients in an active treatment stage were recruited from 2 hospitals between October and December 2010. A survey including perceived health status, physical functional status, the symptom experience index, resilience, and the functional assessment of cancer therapy-colorectal (FACT-C) was completed. Results: The level of FACT-C was 86.61 (${\pm}18.91$), which was higher than for patients with colostomy, but lower than for patients in a rehabilitation stage. Participants without physical functional limitations showed higher level of both resilience and quality of life. Participants with bad health status showed a lower level of both resilience and quality of life and higher level of symptom experience. The quality of life was related to the level of resilience (${\beta}$=.373), symptom experience (${\beta}$=-.292), and perceived health status (${\beta}$=-3.961). Conclusion: Proactive nursing approaches to manage symptoms and to improve perceived health status would enhance the quality of life of colorectal cancer patients. Furthermore, various strategies to strengthen the level of resilience should be developed.

A Study on the Calculation Process of Carbon Dioxide Emission for Buildings with Life Cycle Assessment (건축물 생애과정에서의 이산화탄소 배출량 계산 프로세스에 관한 연구)

  • Jeong, Young-Sun;Huh, Jung-Ho
    • Journal of the Korean Solar Energy Society
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    • v.31 no.1
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    • pp.23-30
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    • 2011
  • International cooperation to reduce greenhouse gas emissions is expected to provide a big crisis and a great opportunity at the same time for our industry that heavily consumes energy. To cope actively with the international environmental regulation, such as the Framework Convention on Climate Change, quantitative measurement of the volume of greenhouse gases emitted by various industries and quantitative prediction of the greenhouse gas emissions of the future are becoming more important than anything else at the national level. This study aims to propose the calculation process of carbon dioxide($CO_2$) emission for building in life cycle. This paper describes and compares 9 different tool for environmental load estimation with LCA. This study proposed the calculation process for quantitatively predicting and assessing $CO_2$ emissions during the life cycle of buildings based on the life cycle assessment(LCA). The life cycle steps of buildings were divided into the design/supervision, new construction, repair, renovation, use of operating energy in buildings, maintenance, and reconstruction stage in the life cycle inventory analysis and the method of assessing the environmental load in each stage was proposed.

The Trajectory of Fatigue and Quality of Life in Stomach Cancer Patients Receiving Chemotherapy (위암환자의 항암 화학요법에 따른 피로와 삶의 질 변화 양상)

  • 양영희
    • Journal of Korean Academy of Nursing
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    • v.32 no.4
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    • pp.482-491
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    • 2002
  • This study aimed to identify the change patterns of fatigue and quality of life during consecutive chemotherapies and to determine the relationship of these two variables. Method: Stomach cancer patients receiving chemotherapy were recruited from a university hospital in Seoul. Each chemotherapy, subjects were asked to respond to the questionnaires regarding their fatigue and quality of life. The number of subjects who completed 4 cycles and over was 11. Fatigue was measured with Lee's tool(1999). Quality of life was measured with a tool revised by the author based on Padilla et al(1983). Result: Most patients were in 1st stage(5 patients) or 3rd stage(5 patients). Fatigue was revealed at its highest level in the 3rd or 4th chemotherapy and at its lowest level in the 1st or 6th chemotherapy. A quality of life appeared at its highest level in the 5th or 6th chemotherapy and the lowest level in 3rd or 4th chemotherapy. Conclusion: Among 6 cycles of chemotherapy, in 3-4th chemotherapy the fatigue was the highest and the quality of life were the lowest. Many patients decided to stop treatment at the same period. Therefore we can recognize cancer patients receiving chemo- therapy are in the highest risk at the time of the 3-4 th chemotherapy.

Life Cycle Model of Over lapped-Concur rent Software (중첩-동시개발 소프트웨어의 생명주기 모델)

  • Choi, Myeong-Bok;Han, Tae-Yong;Lee, Sang-Un
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.2
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    • pp.23-34
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    • 2014
  • Though a dozen of different software life cycle models are suggested, there is no universal model which can satisfy all the characteristics of software. Organizations mix and match different life cycle models to develop a model more tailored for their systems and capabilities. We suggest overlapped-concurrent development life cycle model that is more suitable in various software development environment. Firstly, we divided the development process into abstract and implementation stage. Abstract stage is from software concept phase to detailed design starting time, and implementation stage is from detailed design phase to system testing phase. Next, the abstract stage introduced the overlapped phase concept that begins the next phase when the step is completed 20% by applying pareto's law. In the implementation stage, we introduced the concurrent development which the several phases are performed some time as when one use-case (UC) is completed the next development phase is started immediately. The proposed model has an advantage that it can reduce the inefficiency of development resource greatly. This model can increase the customer satisfaction with a great product at a low cost and on a short schedule. Also, this model can contribute to increase the software development success rate.

Life-Cycle Assessment of Technological Processes

  • Graedel, T.E.
    • Clean Technology
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    • v.2 no.2
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    • pp.44-50
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    • 1996
  • "Pollution prevention" is an important and appropriate part of efforts to minimize the environmental impacts of industrial processes, but it is only a part. Even more important is to assess the environmental characteristics of processes across all stages of their lives. This paper presents a formalism for evaluating the environmental implications of processes at each life stage(a procedure termed "life-cycle assessment").

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A Schematic Estimation Development of the CO2 Emission in the Maintenance of Repair of Apartment Housing (개·보수 유지관리부문의 이산화탄소 배출량 간이 산정방법에 관한 연구)

  • Lee, KangHee;Ahn, YoungHan;Chae, ChangU
    • KIEAE Journal
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    • v.13 no.6
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    • pp.99-104
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    • 2013
  • Many activities associated with the construction and habitation of buildings are connected with issues affecting the environment such as global warming, climate change, and consumption of valuable natural resources such as fossil fuels. To minimize negative impacts on the environment, the building industry worldwide has implemented green building practices in many countries. One of the main green strategies is to reduce greenhouse gas emissions caused by residential structures because they are most substantially connected with global warming and climate change. To determine the actual quantity of green house gas emissions caused by the construction and use of a building, it is important to analyze total greenhouse gas emissions over the life cycle of buildings including construction, operation & maintenance(O&M) and demolition stages. Many studies suggest methods to calculate greenhouse gas emissions at the construction stage, but the literature addressing greenhouse gas emissions at the O & M stage is limited. A year-long study was conducted utilizing the deterioration method to calculate greenhouse gas emissions at the O & M stage of building life for condominium types of buildings in South Korea. Through this research, it is possible to analyze greenhouse gas emissions of buildings at the O & M stage, the longest span of the life cycle, and eventually help to calculate total greenhouse gas emissions over the life cycle of the building.

Environmental Life Cycle Assessment (LCA) of Polymer Electrolyte Membrane Fuel Cell (PEMFC) System (Polymer Electrolyte Membrane Fuel Cell 시스템의 환경 전과정평가)

  • KIM, HYOUNGSEOK;HONG, SEOKJIN;HUR, TAK
    • Transactions of the Korean hydrogen and new energy society
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    • v.29 no.1
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    • pp.111-116
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    • 2018
  • The environmental impacts of a 1 kW polymer electrolyte membrane fuel cell (PEMFC) system are quantitatively assessed by performing a Life Cycle Assessment (LCA) study. A PEMFC system produces electricity and heat simultaneously, so an appropriate allocation of associated inputs and outputs is performed between the electricity and heat produced. The environmental impacts of the PEMFC system on the impact categories such as global warming (GW), abiotic depletion (AD), acidification (AC), and eutrophication (EU) are assessed from the life cycle impact assessment. The impact indicator results of the impact assessment on these impact categories are obtained as $3.70E-01kg\;CO_2\;eq./kWh$, 1.86E-03 kg Sb eq./kWh, $4.09E-04kg\;SO_2\;eq./kWh$, and $1.88E-05kg\;PO_4{^{3-}}/kWh$, respectively. For all impact categories studied the most influential stage is the operation stage, which accounts for 98.8%, 98.7%, 70.3%, and 62.3% of the total impact on GW, AD, AC, and EU, respectively. For the impact categories of AD, AC, and EU, most of the environmental impacts during the operation stage is attributed to the production of city gas. However, for the impact category of GW, $CO_2$ emission from the reforming process of city gas is the main reason for the largest contribution of the operation stage to the total impact results.