• Title/Summary/Keyword: Power law

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Steady Shear Flow Properties of Aqueous Poly(Ethylene Oxide) Solutions (폴리에틸렌옥사이드 수용액의 정상유동 특성)

  • Song, Ki-Won;Kim, Tae-Hoon;Chang, Gap-Shik;An, Seung-Kook;Lee, Jang-Oo;Lee, Chi-Ho
    • Journal of Pharmaceutical Investigation
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    • v.29 no.3
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    • pp.193-203
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    • 1999
  • In order to investigate systematically the steady shear flow properties of aqueous po1y(ethylene oxide) (PEO) solutions having various molecular weights and concentrations, the steady flow viscosity has been measured with a Rheometrics Fluids Spectrometer (RFS II) over a wide range of shear rates. The effects of shear rate, concentration, and molecular weight on the steady shear flow properties were reported in detail from the experimentally measured data, and then the results were interpreted using the concept of a material characteristic time. In addition, some flow models describing the non-Newtonian behavior (shear-thinning characteristics) of polymeric liquids were employed to make a quantitative evaluation of the steady flow behavior, and the applicability of these models was examined by calculating the various material parameters. Main results obtained from this study can be summarized as follows: (1) At low shear rates, aqueous PEO solutions show a Newtonian viscous behavior which is independent of shear rate. At shear rate region higher than a critical shear rate, however, they exhibit a shear-thinning behavior, demonstrating a decrease in steady flow viscosity with increasing shear rate. (2) As an increase in concentration and/or molecular weight, the zero-shear viscosity is increased while the Newtonian viscous region becomes narrower. Moreover, the critical shear rate at which the transition from the Newtonian to shear-thinning behavior occurs is decreased, and the shear-thinning nature becomes more remarkable. (3) Aqueous PEO solutions show a Newtonian viscous behavior at shear rate range lower than the inverse value of a characteristic time $1/{\lambda}_E$, while they exhibit a shear-thinning behavior at shear rate range higher than $1/{\lambda}_E$. For aqueous PEO solutions having a broad molecular weight distribution, the inverse value of a characteristic time is not quantitatively equivalent to the critical shear rate, but the power-law relationship holds between the two quantities. (4) The Cross, Carreau, and Carreau-Yasuda models are all applicable to describe the steady flow behavior of aqueous PEO solutions. Among these models, the Carreau-Yasuda model has the best validity.

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Validity and Expected Effect of International Marketing Cooperative for Korean Animation (애니메이션 해외 배급 활성화를 위한 마케팅 협동조합 도입의 타당성 연구)

  • Kim, Young Jae
    • Cartoon and Animation Studies
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    • s.36
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    • pp.121-145
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    • 2014
  • Operating under the principle of user-benefit maximization and democratic user-control, cooperatives are being spot-lighted as a business model satisfying the various social, financial needs. In Korea, the Law of Cooperative was enacted as of December 2012, which has enabled the establishment of cooperatives in variety of industry fields. This study is to discuss the expected effect and validity of marketing cooperative as a solution for insufficient sales revenue in international distribution of Korean animation. The interviews with Korean animation studios found out the key problems of overseas distribution, which are; 1) lack of marketing expertise and weak organization, 2) lack of ancillary rights exploitation due to the deals based upon all rights package with the broadcasters who are not interested in ancillary business, 3) lack of localized marketing support in each territory. The solution for these problems takes large and long-term marketing investment and it is far beyond the capabilities of small Korean animation studios. Marketing cooperative can provide services not available otherwise such as in-depth market research which will help the improvement of international marketing expertise. Also. as the cooperative carries enough volume of animation catalogue, it can increase negotiation power satisfying the various needs of buyers. Also, it can provide the precise marketing support for each territory by integrating every process of value chain, from TV broadcasting, merchandising, and digital media platform. Above all, a clear benefit of marketing cooperative is that, because of its user-benefit and user-control principle, the principal-agent problem can be minimized while it maximizes the profit for member studios.

Effect of Styrene and Maleic Anhydride Content on Properties of PP/Pulp Composites and Reactive Extrusion of Random PP (랜덤 PP의 반응압출 및 PP/Pulp 복합체 특성에 대한 스티렌과 무수말레인산 함량의 영향)

  • Lee, Jong Won;Kim, Ji Hyun;Kim, Youn Cheol
    • Applied Chemistry for Engineering
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    • v.25 no.3
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    • pp.318-323
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    • 2014
  • In order to analyze the effect of maleic anhydride (MAH) content and styrene monomer (SM)/MAH mole ratio on reactive extrusion of maleic anhydride grafted random polypropylenes (MAH-g-rPP), MAH-g-rPPs were prepared by using a twin screw extruder. MAH contents were 0.5, 1.0, 3.0, and 5.0 phr and SM/initiator mole ratio was 0.0, 1.0, and 2.0. Dicumyl peroxide (DCP) was used as an initiator. The graft degree of MAH was confirmed by the existence of carbonyl group (C = O) stretching peak at $1700cm^{-1}$ from FT-IR spectrum. The degree of graft reaction increased up to 3.0 phr MAH and showed the optimum value at 1.0 SM/MAH mole ratio from the area ratio of C = O and C-H stretching peak. Thermal and crystallization properties of MAH-g-rPP and PP/MAH-g-rPP/pulp composites were investigated by DSC, TGA, XRD, and POM. There was a decrease in non-isothermal crystallization temperature of PP/MAH-g-PP/pulp composites. Based on tensile properties and SEM pictures for the fractured surface of PP/MAH-g-PP/pulp composites, MAH content of 1.0 wt% and SM/MAH mole ratio of 1.0 were the optimum formulation as the compatibilizer. The rheological properties of the composites were measured by dynamic Rheometer to compare the processability of the composites with and without compatibilizer. The power law index showed slightly low value at the composites with compatibilizer.

Study on the Modeling Technique for Prediction about Pressure Drop of an Intravenous Lung Assist Device (혈관 내 폐 보조장치의 압력손실 예측을 위한 모델링기법에 관한 연구)

  • 김기범;권대규;정경락
    • Journal of Biomedical Engineering Research
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    • v.24 no.4
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    • pp.293-299
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    • 2003
  • In this paper, the correlation of Pressure drop about the Newtonian and non-Newtonian fluid was investigated experimentally for vibrating intravascular lung assist device (VIVLAD) and we determined correlation equation to make a prediction about Pressure drop for designing VIVLAD. Design conditions to predict the pressure drop of the modules were studied through an experimental modeling before inserting the artificial lung assist device into as venous. Experiments were performed by distilled water, glycerol/water mixed solution(40% glycerol) of Newtonian fluids. and the bovine blood of non-Newtonian fluids. These fluids were flowed outside and parallel of hollow fiber membranes. Also we measured pressure drop according to the number of the fiber membranes which ware inserted into the inside diameter of shell of 3 cm, and developed the prediction equations by curve fitting method based on correlation between the experimental pressure drop and the frontal area or the packing density of device. The result showed that the Pressure drop and the friction factor of the water/glycerol mixed solution were similar to that of bovine blood. It was showed that the water/glycerol mixed solution (40% glycerol) could be used for measuring the pressure drop and the friction factor instead of the bovine blood. Also, we could estimate the prediction equation of pressure drop and friction factor as the function of Packing density at the number of hollow fibers. We obtained the reliance of the prediction equations because the pressure drop and the friction factor measured from the experiments were similar to that from the prediction equation. These results may be used to further usefulness for the design of VIVLAD.

Performance Ability after CPR Education of the ground workers in an airport (공항 지상 근무자의 심폐소생술 수행능력)

  • Shin, Ji-Hoon
    • The Korean Journal of Emergency Medical Services
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    • v.13 no.3
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    • pp.29-40
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    • 2009
  • Objective : This study is an experimental study which is designed to examine the differences between knowledge and self-confidence before and after theory education(CPR PPT material) based on guidelines of CPR and emergency cardiac treatment of American Heart Association(AHA, 2005) and video self-instruction program for the general public by Korean Association of Cardiopulmonary Resuscitation(KACPR), trace CPR performance ability after CPR and AED education and investigate the accuracy of artificial respiration and chest compression, and know the difference in CPR performance abilities including AED. Methods : Subjects of this study include ground crews and staffs at M airport in G province equipped with emergency equipments for CPR according to Art. 47, Sec. 2 of Emergency Medical Law, airport police, rent-a-cops, security guard, quarantine officer, custom officer, and communication, electricity, civil engineering, facility management staff, airport fire fighting staff, air mechanic, traffic controller, and airport management team among airport facility management staffs. They were given explanation of necessity of research and 147 of 220 subjects who gave consent to this research but 73 who were absent from survey were excluded were used as subjects of this study. of 147 subjects, there were 102 men and 45 women. Results : 1) Knowledge score of CPR was $6.18{\pm}0.87$ before instruction and it was increased to $15.12{\pm}1.78$ after instruction, and there was statistically significant difference. 2) Self-confidence score in CPR was $3.16{\pm}0.96$ before instruction and it was increased to $7.05{\pm}0.75$ after instruction, and there was statistically significant difference. 3) Total average score in CPR performance ability after instruction was 7.46 out of 9, performance ability was highest in confirmation of response as 144(97.95%), follwed by request of help as 140(95.25%) and confirmation of respiration as 135(91.83%), and lowest in performing artificial respiration twice(gross elevation of chest) as 97(65.98%). Accuracy of artificial respiration(%) was $28.60{\pm}16.88$ and that of chest compression(%) was $73.10{\pm}22.16$. 4) Performance ability of AED after instruction showed proper performance in power on by 141(95.91%) and attaching pad by 135(91.83%), hand-off for analyzing rhythm showed 'accuracy' in 115(78.23%) and 'non-performance' in 32(21.77%), delivery of shock and hand-off confirmation showed 'accuracy' in 109(74.14%) and 'inaccuracy' in 38(25.86%), and beginning chest compression immediately after AED was done by 105(71.42%).

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A Study on the Feasibility of the Espionage Charges for the Industrial Technology Divulgence (산업기술의 해외유출행위에 대한 간첩죄 처벌 타당성 연구)

  • Kim, Hang-Gon;Lee, Chang-Moo
    • Korean Security Journal
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    • no.57
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    • pp.253-275
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    • 2018
  • Economic security emerged as a strong element of national security. Nations around the world are exerting their efforts to collect economic intelligence to serve their national interest while making added efforts to uncover industrial espionage and arrest industrial spies in defensive aspect. Cases in point are the enactment of "Economic Espionage Act(1996)" of the U.S. and the "Act on Prevention of Divulgence and Protection of Industrial Technology(2006)"of Korea. Korea is trying to punish industrial spying on the same level as espionage that poses national security threat by revising Criminal Code. It is necessary to review whether the move to toughen the punishment of industrial spying from "up to 15 years in prison and/or up to 1.5 billion won in fine" to "minimum seven years of imprisonment, life imprisonment or death penalty" is appropriate. Advanced nations regulate industrial spying with a special act on economy although they have applied espionage act not to "enemy states" but to "foreign countries" in the first place. Likewise, preventing industrial spying by applying espionage act through the revision of criminal code poses a risk of undermining the autonomy of industry sector by excessive influence of state power. Furthermore, the penalty of minimum imprisonment of seven years, life imprisonment or death penalty with the application of espionage act under the criminal code is an legal application by stretching of the law, posing a risk of dampening healthy economic activities. Therefore, revising and applying relevant economic laws such as aforementioned 'Act on Prevention of Divulgence and Protection of Industrial Technology(2006)' is thought to be desirable to achieve the goal of protecting industrial technologies.

A Life-History Approach to the Practice of Early Marriage in Ethiopia (에티오피아의 조혼 관습에 대한 생애사적 접근)

  • Seol, Byung-Soo
    • Cross-Cultural Studies
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    • v.42
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    • pp.69-106
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    • 2016
  • Early marriage in contemporary society has brought about many problems. The practice is encouraged by gender inequality, poverty and social norms. It reproduces social power imbalances including increased economic vulnerability of women, low educational attainment of girls, gender inequality at home and in the labor market, physical and sexual violence against women and their health problems. The Ethiopian government increased the minimum legal age of marriage for women from 15 to 18 years, by revising its family code in 2000 and newly adopting a criminal law in 2005 that includes punishment against any harmful tradition. Nonetheless, early marriage is still widely practiced in many parts of rural Ethiopia. This is because the practice has long been embedded and deeply rooted in the lives of the people. Earlier literature on early marriage in Ethiopia tends to focus only on women's experiences and regard that all early-married people, particularly women, are unhappy with their lives. This paper attempts to explore the issue of early marriage through voices of people with diverse socioeconomic backgrounds, in order to address the limitations of the previous literature. This article aims at examining why early marriage has occurred in Ethiopia and how it has affected family life and women's educational attainment, focusing on the case of Meki town. As seen from this study, it is true that early marriage generally had negative influences on the lives of women. However, it is equally true that some men are also victims of the practice while some women have improved their lives by means of it. This implies that we need to listen to the voices of diverse people when we examine early marriage.

Characterization of Ecological Networks on Wetland Complexes by Dispersal Models (분산 모형에 따른 습지경관의 생태 네트워크 특성 분석)

  • Kim, Bin;Park, Jeryang
    • Journal of Wetlands Research
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    • v.21 no.1
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    • pp.16-26
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    • 2019
  • Wetlands that provide diverse ecosystem services, such as habitat provision and hydrological control of flora and fauna, constitute ecosystems through interaction between wetlands existing in a wetlandscape. Therefore, to evaluate the wetland functions such as resilience, it is necessary to analyze the ecological connectivity that is formed between wetlands which also show hydrologically dynamic behaviors. In this study, by defining wetlands as ecological nodes, we generated ecological networks through the connection of wetlands according to the dispersal model of wetland species. The characteristics of these networks were then analyzed using various network metrics. In the case of the dispersal based on a threshold distance, while a high local clustering is observed compared to the exponential dispersal kernel and heavy-tailed dispersal model, it showed a low efficiency in the movement between wetlands. On the other hand, in the case of the stochastic dispersion model, a low local clustering with high efficiency in the movement was observed. Our results confirmed that the ecological network characteristics are completely different depending on which dispersal model is chosen, and one should be careful on selecting the appropriate model for identifying network properties which highly affect the interpretation of network structure and function.

A Study on the Necessity of Verification about depot level maintenance plan through the Weapons System cases analysis (무기체계 사례 분석을 통한 창정비개발계획안 검증 필요성 연구)

  • Ahn, Jung-Jun;Kim, Su-Dong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.2
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    • pp.76-82
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    • 2019
  • This study has done to search for a solution to remove risk limitedly caused by separating weapon system acquisition from operation and maintenance at the view point of Logistic Commander who's responsible for stable operation and maintenance after acquiring weapon system. At the System development stage, unverified overhaul development plan may cause additional manpower and costs after the development, and furthermore it is likely to have risk to lower reliability of the military. Thus, research and development agency should write overhaul development plan at the System development stage, and it should be verified through evaluation and verification test. Secondly, during research and development, institutional supplementation is needed to calculate human and material resources writing overhaul development plan. Thirdly, it should be able to analyze proper operation & maintenance plan and cost for overhaul plan at the pre-investigation stage. Fourthly, the base which can develop overhaul concept and overhaul factors should be included in the need and need determination document. Lastly, for the weapon system which has small amount of high power figure, project management should be performed to be able to specify at the each acquisition level of weapon system to realize Article 28, clause 3 and 4 of Defense business law.

A Study on the Improvement Plan of the Urban Area Using the Three-Dimensional Road System -Focus on Shinbashi·Toranomon area in Japan- (입체도로제도를 활용한 도심 정비방안에 관한 연구 -일본 신바시, 토라노몬 재개발사업을 중심으로-)

  • Baek, Seung-Kwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.11
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    • pp.213-223
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    • 2018
  • This study assessed the maintenance plan of the Shimbashi-Toranomon Development Area in Japan, which has recently been completed using the three-dimensional road system. In the main relevant law system, a three-dimensional road system, which enables the construction of buildings above and below the road, was applied. The specific construction regulations applying the financing power and knowledge of private business operators were applied. In the development district, city maintenance guidelines were established, and housing and shopping malls were regulated. This purpose was to promote change, unity of distance, effective use of land, and continuous urban revitalization with charm and vitality. The main features of the maintenance plan were accessibility and greenery, comfort and a sophisticated design, and a maintenance concept utilizing historical buildings and road space through the participation of local residents and the opinions of related committees. In addition, in the case of the construction of the upper and lower roads, the construction restrictions were relaxed, and the separation of the roads and the undergrounding of electric poles were promoted. The main aim was to improve the convenience of the residents and produce a pleasant road landscape.