• Title/Summary/Keyword: Forming limits

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Quantitative Evaluation of Plasticity and Extension for Extruding Body (압출성형용 소지의 가소성과 연신율의 정량화)

  • Bae, Won-Tae;Shin, Dong-Woo
    • Journal of the Korean Ceramic Society
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    • v.39 no.11
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    • pp.1048-1054
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    • 2002
  • When forming the ceramic body with plastic mass, it is needed that a quantitative testing method for plasticity, not only to evaluate the plasticity of a body, but also to control it within limits. Although many testing instruments were introduced, but no handy testing instrument for the plasticity quantitatively has been developed. In this study, modified vicat needle was designed to handily evaluate the plasicity of extruding bodies for honeycomb. The plasticity of three plastic masses was tested with this equipment. Columned needle with 2 mm diameter was adopted to measure the resistance for deformation and spherical needle with 9.5 mm diameter was adopted to measure the amount of deformation before cracking. The plasticity of three tested bodies were clearly distinguished quantitatively each other and the testing results were helpful to evaluated the workability of theses bodies. Probably, it is possible to evaluate the plasticity of various ceramic bodies with this apparatus, if suitable diameters of columns and spheres are selected.

Development of Shape refining process of VLM-ST Parts Using Noncontacting Hot Tool (비접촉식 열공구를 이용한 VLM-ST 제품의 미세 형상 가공 공정 개발에 관한 연구)

  • 김효찬;이상호;안동규;양동열
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.1
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    • pp.149-158
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    • 2004
  • In most RP processes, the inherent stair-stepped surfaces and shrinkage-induced warping of the parts require post processing such as surface finishing. To minimize such defects, VLH-ST, a newly developed RP process, employs a 3.9-mm thick expandable polystyrene (EPS) foam sheet and a hot wire to contour it to have slant linear-interpolated sides. The use of relatively thick sheets for layers, however, limits the process capability of constructing fine details, especially smaller than the layer thickness. This study is focused on the development of a post processing method fo fine details of VLM-ST parts. The post-processing tool was designed to meet all the requirements for the desirable post processing. It adopted a hot wire as a means of melting the EPS foam sheet. Various basic experiments on the post processing were carried out to obtain the optimal process conditions. The dominant process parameters such as the radiated heat input, the tool speed, and the gap between the tool tip and the foam sheet (tool height) were considered in the experiments. The effectiveness of the developed post-processing method fo forming or engraving fine details on the VLM-ST parts has been thus demonstrated. The experiments on engraving several sets of letters, such as CANESM, 인간, and 한국과학기술원, on the EPS foam sheet were carried out. In addition, a flowery shape was engraved on a three-dimensionally curved surface of a pottery-shape VLM-ST part.

Evaluation of Strain, Strain Rate and Temperature Dependent Flow Stress Model for Magnesium Alloy Sheets (마그네슘 합금 판재의 변형률, 변형률 속도 및 온도 환경을 고려한 유동응력 모델에 대한 연구)

  • Song, W.J.;Heo, S.C.;Ku, T.W.;Kang, B.S.;Kim, J.
    • Transactions of Materials Processing
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    • v.20 no.3
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    • pp.229-235
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    • 2011
  • The formability of magnesium alloy sheets at room temperature is generally low because of the inherently limited number of slip systems, but higher at temperatures over $150^{\circ}C$. Therefore, prior to the practical application of these materials, the forming limits should be evaluated as a function of the temperature and strain rate. This can be achieved experimentally by performing a series of tests or analytically by deriving the corresponding modeling approaches. However, before the formability analysis can be conducted, a model of flow stress, which includes the effects of strain, strain rate and temperature, should be carefully identified. In this paper, such procedure is carried out for Mg alloy AZ31 and the concept of flow stress surface is proposed. Experimental flow stresses at four temperature levels ($150^{\circ}C$, $200^{\circ}C$, $250^{\circ}C$, $300^{\circ}C$) each with the pre-assigned strain rate levels of $0.01s^{-1}$, $0.1s^{-1}$ and $1.0s^{-1}$ are collected in order to establish the relationships between these variables. The temperature-compensated strain rate parameter which combines, in a single variable, the effects of temperature and strain rate, is introduced to capture these relationships in a compact manner. This study shows that the proposed concept of flow stress surface is practically relevant for the evaluation of temperature and strain dependent formability.

Rapid Screening of Salmonella spp. Using PBM BioSignTM Salmonella Test and Evaluation of the PBMS Test

  • Lim, J.Y.;Kwon, N.H.;Kim, J.M.;Jung, W.K.;Park, K.T.;Hong, S.K.;Park, Y.H.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.12
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    • pp.1746-1750
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    • 2004
  • The PBM ${BioSign}^{TM}$ Salmonella (PBMS) test kit based on an mmunochromatographic method was evaluated for the screening of Salmonella spp. in pure cultures, and 80, 15, and 10 artificially and naturally contaminated, and negative controlled food samples, respectively. The PBMS test involves presumptive qualitative procedures, detecting the presence of Salmonella spp. in foods within 26 h total testing period and allowing the user to release negative products 70 h earlier than the conventional methods. The PBMS test using Buffered Peptone Water and Rappaport-Vassiliadis broth was evaluated for 10 different food types for various Salmonella spp. It showed detection limits of 1 to 25 colony forming units (CFU)/25 g. No cross-reaction was observed, particularly to other gramnegative bacteria. These results indicate the PBMS test is a rapid and inexpensive procedure for the screening of Salmonella spp. present at low concentrations (1 to 25 CFU/25 g) in foods.

A Study on the Meaning and the Factors of Formation of the Prototypal Landscape (원형경관(原型景觀)의 개념 정립 및 형성요인 연구)

  • Kang, Young-Eun;Choi, Dong-Wook;Hong, Sung-Hee;Jung, Yun-Hee;Kim, Sang-Bum;Im, Seung-Bin
    • Journal of Korean Society of Rural Planning
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    • v.15 no.4
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    • pp.33-42
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    • 2009
  • This study is aimed at the necessity application in 'Prototype' general concept on discovering cultural identity landscape of our national characteristics landscape research. Accordingly, It is considered landscape, fundamental concept, the prototypal landscape concept from previously researches that have been used. At the same time, the concept of prototypal landscape has been established by commenting a point of view which is defining previous researches that controverted prototypal landscape, then establish concept of prototypal landscape and derive attribute by comparing and considering similar terminology of prototypal landscape. Previously, research prototypal landscape in depth by applying defined concept of prototypal landscape and considering inherence ideological and environmental background prototypal figure and structure. Formation pattern of the prototypal landscape is classified in both philosophical formative primary factor from philosophy, religion and environmental formative factor of human that accumulated cultural life from a region and life. Examples of forming the prototypal landscape by philosophical formative factor are classified as 'Feng-Shui(the theory of divination based on topography)', 'Yin-Yang theory', 'Confucian idea theory' 'Philosophical Taoism', 'Buddhism theory' and 'Nature theory' then environmental formative factor are interpreted by 'Taekliji(determining of advantageous land)', 'Imwon(forest) economical geography', 'land use', 'topography' and 'terrain' as examples. This study is anticipating a new point of view and an establishment of reliable preservation to our characteristic of the prototypal landscape by considering concept of prototypal landscape and formative factor as studying limits of prototypal landscape and researching concentrated origination of the prototype.

Influence of Chemical and Mechanical Treatments of the Screened Short Fibers from OCC on Paper Properties -Strength Property Improvement of OCC-based Paper by Chemical and Mechanical Treatment (IV)- (골판지 고지섬유의 단섬유분의 물리화학적 처리에 관한 연구 -골판지 고지의 물리화학적 처리에 의한 강도향상 제4보-)

  • Lee, Jong-Hoon;Seo, Yung B.;Choi, Chan-Ho;Jeon, Yang
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.33 no.4
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    • pp.7-14
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    • 2001
  • Recycled fibers usually give slow drainage in the paper forming process, which limits the application of more refining to the recycled fibers for improving paper strength and formation. To use recycled fibers more effectively, especially OCC, developing very efficient handling technique of short fibers and fines is inevitable. We tried to make hard flocs of fractionated short fibers and fines, which were the main cause of slow drainage, by adding excessive amount of retention aid selectively on them. This technique was proved to increase drainage considerably, but to decrease strength properties, compared to the conventional technique of adding the same amount of polymers to the whole furnish in the lab test. The bonding capability of short fibers and fines in Korean OCC was very poor. Various chemical treatment on the short fibers and fines of the Korean OCC did not improve their bonding and optical properties. One of the reasons of no improvement in their properties was their high amount of ashes.

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Emerging Currents in Health and Medicine - A Socio-Cultural Critique of Their Discourses and Practices - (건강과 의학의 새로운 흐름 - 담론과 실천 방식에 관한 사회문화적 비평 -)

  • 이종찬
    • Health Policy and Management
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    • v.10 no.4
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    • pp.1-19
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    • 2000
  • We have witnessed several kinds of new discourses and practices in health and medicine since the 1970s, such as popular concerns with alternative or complementary medicine, inordinate attention to the promotion of 'healthy' living, rapid resurrection of traditional medicine and ecological management of health. Four structural and situational factors are discussed to underlie these new trends:(i) as 'crisis' in health care of the 1970s was translated into health care reform of the 1980s backed up by neo-liberal political philosophy, the state responsibility for nation's health is being transferred to the individual ;(ii) it resulted from the limits of biomedical paradigm in dealing with chronic diseases;(iii) medico-scientific knowledge of disease is transformed into the subjective discourses and technologies of health in postmodern society ; and (iv) it is deeply associated with the considerable increase in environmental risk perception of health and disease. There are some inherent countervailing forces in these new discourses and practices. First, while they derive from lifestyle-oriented behavioral change, medicalization of life and death is still consolidated in the new trends. Second, inasmuch as new tides are reliant upon science, they. are likely to be remote from techne that means not the practical application of theoretical knowing but a special form of practical knowing. Third, as new discourses and activities accomplished'in the name of health'increasingly occupy important strategies in forming the self-identity, they serve as moral apparatus which involves prescriptions about how we should live our lives and conduct our bodies, both individually and collectively. Therefore, two points are suggested to consider seriously whether these streams will succeed in improving the‘healthy’living of all the people. Instead of limiting tile perspective to medicine, healing and health care, a new matrix that interweave welfare, ecology and labor along with them is timely needed for enhancing the health for all. In addition, as the World Health Report fm strongly shows, inequality in health heavily depends upon socio-economic development of a society, and it is not the richest countries that have the best health status, but those that have the smallest income differences between rich and poor.

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Factors to Influence Customer Satisfaction and Future Behavior Intention for LOHAS Exhibition (로하스박람회의 고객만족과 미래행동의도에 미치는 영향요인)

  • Ra, Jeung-Im;Kim, Hyoung-Gil;Yang, Sung-Soo
    • Journal of Distribution Science
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    • v.14 no.9
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    • pp.133-147
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    • 2016
  • Purpose - The Purpose of this study is to observe the value of LOHAS as an exhibition that is perceived to be a specialized local exhibition with good fame and differentiated advantage as well as the spectators' will to visit the exhibition coming from the future behavior intention of visitors. Research design, data, and methodology - In order to achieve the purpose of this study, This study organized questionnaire after setting a hypothesis based on the theoretical background from the parameters. verification of the hypothesis by statistically analyzing the answers for questionnaire follows. Finally, the implication of this study is drawn through comprehensive discussion while This study indicated from the limits of the study and future direction for research. This study set up a model to research the influence on the structuring factors in LOHAS exhibition in forming perceived value, customer satisfaction and future behavior intention. Frequency analysis was used for getting demographic characteristics, verification of plausibility, reliability of measured parameters and factors analysis. This study have performed verification of difference at selection property level based on multiple regression analysis and demographic nature. Results - To summarize the study result, through the verification of hypothesis about meaningful influence among structuring factors in LOHAS exhibition, perceived value and customer satisfaction shows some noticeable points to focus on. That is, it is established things that partial adoption and meaning relationship of partial influence. The perceived value affected both customer satisfaction and future behavior intention meaningfully. Conclusions - This study could note that in the structuring factors of LOHAS exhibition, perceived value for visitors and customer satisfaction play their roles positively on the future behavior intention. In conclusion, this study implies that strategic measures are necessary to fulfill the structuring factors of LOHAS exhibition as they would make positive impact on acknowledged value, customer satisfaction and future behavior intention to contribute to the growth and development of LOHAS exhibition. Also it suggests that the method to join each other with activities is necessary to strengthen the properties of the exhibition and position well to be a solid local exhibition.

A Study on the Korean Fishery Management System and TAC System Implementation on Issues of the New Ocean Regime (신해양질서의 어업관리체계와 TAC 제도 도입에 관한 연구)

  • 이상고
    • The Journal of Fisheries Business Administration
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    • v.30 no.1
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    • pp.1-29
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    • 1999
  • When the international fisheries order changes following the UN Law of the Sea, the new regional fisheries order is forming among East North Asian states and era of Economic Zones is really coming. In those changes of foreign and domestic fisheries environment, to maintain sustainable growth of the industry in 21st century the North East Asian states plot adjustments to fisheries management, such as introduction of the TAC system and others. The TAC seems to be an appropriate systematic response especially because traditional functions of fisheries management have already demonstrated their limits in regards to fisheries sustainable development. Introduction of the TAC to the North East Asian fisheries not only resolves the inability of traditional fisheries management to develop the industry consequently, but also strengthens the EEZ and existing marine management systems. However, the TAC was born by thewestern industrial mentality, still contains persistent mistakes and is difficult to change. Therefore, its introduction to and implication in North East Asian region might cause numerous problems. From this point of view, introduction of the TAC system will disregard peculiarities of North East Asian fisheries, so main efforts should be concentrated on improving the functions of existing system via consecutive step-by-step approach. In addition, the TAC should be grafted into the existing fisheries system through cooperative management system, creating stable systematic ground and considering scientific and fisheries motives. Especially, TAC system, unlike the traditional fisheries' management system, is scientific, being systematically developed one, and needs to be gradually installed, considering its systematic character. Therefore, the TAC should better be introduced by systematic and scientific approaches, paying more attention to strengthening the existing fisheries system, but not immediately and in the form it is right now. Concluding, introduction of the TAC can not be made considering the outward factors deriving from the UN Law of the Sea without corrections.'h overcome limitations and ineffectiveness of traditional fisheries, most efforts should be concentrated on basic revision of 21st centuries' fisheries and strengthening the functions of traditional fisheries aimed to develop the leading business of marine industries.

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Development of the Speed Limit Model for Harbour and Waterway(II) - The Method of Speed Limit Decision and Application -

  • Kim, Deug-Bong;An, Kwang
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.21 no.3
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    • pp.274-282
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    • 2015
  • This research is the result on calculating the logical speed limit through certain process which some elements must be considered on selecting the speed limit of harbour and waterway. The suggested speed limit select model on this research is processed from 1~6 steps by forming a professional group of experts. Each step has its information which 1st step(water division), 2nd step(selecting the model vessel and vessel applied with speed limit.), 3rd step(selecting the maximum and minimum speed range on each section), 4th step(evaluation on the safeness of traffic), 5th step(suggesting the appropriate speed limit), 6th step(execution and evaluation.). The appropriate speed limit was decided on consideration of the safety of maritime traffic on the range of the maximum speed and the minimum speed. This model was used to derive the appropriate speed limit on the harbour water and Busan harbour entrance waterway. As the result, the harbour water was calculated to be 6.9 knots, the appropriate speed limit of Busan entrance harbour was 9.3 knots. The present calculation of the speed limit on the approaching channel area is 10 knots, inner harbour area is 7 knots, which are similar to the result of the speed limit. This research is the first research on selecting the speed limit model and has its limits on finding the perfect speed limit result. More detailed standards on the safeness of traffic evaluation must be found and additional study is necessary on discriminating consideration of the elements. This research has its value which it provides instances of aboard cases on guidelines of selecting the speed limit.