• Title/Summary/Keyword: chain orientation

Search Result 148, Processing Time 0.026 seconds

Conformation of single polymer molecule in a slot coating flow

  • Lee, Jeong-Yong;Ryu, Bo-Kyung;Lee, Joo-Sung;Jung, Hyun-Wook;Hyun, Jae-Chun
    • Korea-Australia Rheology Journal
    • /
    • v.20 no.2
    • /
    • pp.89-94
    • /
    • 2008
  • To satisfy good mechanical and optical properties of polymer-coated film products, it will be indispensable to elucidate the molecular orientation of polymer chains within coating liquids in coating flows. Using hybridized numerical method between computational fluid dynamics (CFD) and Brownian dynamics (BD) simulations can provide the useful information for the better quality control of coated films. Flexible polymer chains, e.g., ${\lambda}$-DNA molecules here, change their conformation according to the flow strength and the flow type. The molecular conformation within the coated film on the web or substrate is quite different, because the polymer chains experience the complicated flow strength and flow types in flow field. Especially in the slot coating flow, these chains are more extended by the extension-like flow field generated in the free surface curvature just beyond the downstream die region. Also, the polymer chain extension beneath the free surface can be affected by the die geometry, e.g., the coating gap, changing flow field.

Problems and Suggestions for the IT Workforce Training Programs (정부의 IT인력양성정책 대한 문제점과 개선안)

  • Lee Taehee;Yu Jisoo;Ahn SungMahn
    • Journal of Information Technology Applications and Management
    • /
    • v.11 no.3
    • /
    • pp.1-21
    • /
    • 2004
  • To meet the needs of the information age, the Korean government has placed a high priority in building the IT -capable workforce. Though a sizable financial resource was committed in implementing the policy, its effectiveness was not examined yet. The policy for the workforce development should be assessed continuously so that any misdirections are detected and redressed. The present study addresses four potential problems that would not allow the government to switch from a quantity-based policy to a quality-based policy. These are ① Korean universities' labor supply chain. ② moral hazard problems. ③ financial capacity of students, ④ horizontal policy orientation. The paper also proposes solutions to the mentioned problems. The government should foster an environment in which provide the concerned parties(universities. private institutions. students. etc,) with incentives to participate actively and promote the market principle of labor supply and demand. Such an ex-ante approach is believed to improve the system's efficiency compared to the extant approach based on ex-post KPI figures. If the four issues are not redressed. the market failure is likely to occur. The government should not make direct involvement in developing manpower, but rather be a linchpin to pull all concerned parties together. By doing so. the government should be able to fill the gap among parties in the system. One government role would be like defining workforce categories and promoting their career paths. Such role will also trigger universities and private institutions to pursue differential strategies along the supply chain of a particular workforce type.

  • PDF

Corrosion Prediction of Metallic Cultural Heritage Assets by EIS

  • Angelini, E.;Grassini, S.;Parvis, M.;Zucchi, F.
    • Corrosion Science and Technology
    • /
    • v.18 no.4
    • /
    • pp.121-128
    • /
    • 2019
  • Electrochemical Impedance Spectroscopy (EIS) was used to predict corrosion behaviour of metallic Cultural Heritage assets in two monitoring campaigns: 1) an iron bar chain exposed indoor from over 500 years in the Notre Dame Cathedral in Amiens (France); and 2) a large weathering steel sculpture exposed outdoor from tens of years in Ferrara (Italy). The EIS portable instrument employed was battery operated. In situ EIS measurements on the iron chain could be used to investigate the phenomena involved in the electrochemical interfaces among various corrosion products and assess and predict their corrosion behaviour in different areas of the Cathedral. Meanwhile, the sculpture of weathering steel, like most outdoor artefacts, showed rust layers of different chemical composition and colour depending on the orientation of metal plates. The EIS monitoring campaign was carried out on different areas of the artefact surface, allowing assessment of their protective effectiveness. Results of EIS measurements evidenced how employing a simple test that could be performed in situ without damaging the artefacts surface is possible to quickly gain knowledge of the conservation state of an artefact and highlight potential danger conditions.

Determining the adjusting bias in reactor pressure vessel embrittlement trend curve using Bayesian multilevel modelling

  • Gyeong-Geun Lee;Bong-Sang Lee;Min-Chul Kim;Jong-Min Kim
    • Nuclear Engineering and Technology
    • /
    • v.55 no.8
    • /
    • pp.2844-2853
    • /
    • 2023
  • A sophisticated Bayesian multilevel model for estimating group bias was developed to improve the utility of the ASTM E900-15 embrittlement trend curve (ETC) to assess the conditions of nuclear power plants (NPPs). For multilevel model development, the Baseline 22 surveillance dataset was basically classified into groups based on the NPP name, product form, and notch orientation. By including the notch direction in the grouping criteria, the developed model could account for TTS differences among NPP groups with different notch orientations, which have not been considered in previous ETCs. The parameters of the multilevel model and biases of the NPP groups were calculated using the Markov Chain Monte Carlo method. As the number of data points within a group increased, the group bias approached the mean residual, resulting in reduced credible intervals of the mean, and vice versa. Even when the number of surveillance test data points was less than three, the multilevel model could estimate appropriate biases without overfitting. The model also allowed for a quantitative estimate of the changes in the bias and prediction interval that occurred as a result of adding more surveillance test data. The biases estimated through the multilevel model significantly improved the performance of E900-15.

The Impacts of Design Orientation on Brand and Reputation Orientation (기업의 디자인 지향성이 브랜드 및 기업의 명성 지향성에 미치는 영향)

  • Syh, Yong-Gu;Hong, Sung Jun;Yu, jongpil
    • Asia Marketing Journal
    • /
    • v.9 no.1
    • /
    • pp.73-102
    • /
    • 2007
  • The paper aims to examine the relationships among a company's design, brand, and reputation orientations. DBR (Design, Brand, Reputation) have been regarded as invisible growth engines for companies and draws a lot of interests among Brand, PR and IR mangers recently. We have tested 3 hypotheses and have developed a relationship mechanism how to develop those three key intangible marketing assets. We have conducted 131 interviews with company managers who are involved in DBR activities, used Structural Equation Model (SEM) to estimate those relationships. It was found that a company's design orientation influenced the company's brand orientation positively and this brand one influenced reputation orientations consequently. However, design orientation does not show any significant relationship with a company's reputation orientations. Thus, there is a D->B >R chain mechanism concerning these 3 intangible marketing assets. Finally, the implications of this study and suggestions of further studies are discussed.

  • PDF

Profiling Approach for the Choice between Speculation and Postponement Strategy in Supply Chain Management (공급사슬관리의 예측전략과 지연전략 선택을 위한 프로파일링 접근법)

  • Kang, Sung-Wook;Kim, Gyu-Bae
    • Journal of Distribution Science
    • /
    • v.12 no.4
    • /
    • pp.47-54
    • /
    • 2014
  • Purpose - The postponement strategy, which delays the form, place, and production of products as late as possible, has been widely considered as a competitive supply chain management scheme in an era of mass customization and modular manufacturing. An interesting business phenomenon is that not all manufacturing/logistics firms choose the postponement strategy. Given that postponement is a counter-measure to speculation, which has some advantages under certain environments, the current imprudent inclination toward the postponement strategy may cause firms to lose the potential of the speculation strategy, an alternative strategy in supply chain management. Building on the logistics and manufacturing literature, this study examines characteristics of two contrasting strategies, postponement and speculation, and major factors favoring each strategy. Research design, data, and methodology - We apply the profiling approach to two business cases, HP printer and LG mobile phone. The profiling approach is a method of choosing a particular strategy aligned with environmental factors. While various approaches have been used to check the fit between a business strategy and environmental factors, the literature on manufacturing strategy and logistics has commonly adopted the profiling approach. Major factors used in profiling variables are derived from the literature. Two samples, HP printer and LG mobile phone, are selected, because they represent major characteristics appropriate for each strategy. The profiling is based on data from semi-organized interviews with managers. Results - The profiling approach shows that the postponement strategy is a suitable one for HP printers. Most factors, such as product life cycle, large production volume, low-price, product value, and monetary density, support delaying end products until as late as possible. Despite some exceptions, such as delivery time and economy of scale, our analysis states that the overall profile of HP printer is favorable for the postponement strategy. On the other hand, LG mobile phone may adapt the speculation strategy. Although it has large production volume and low delivery frequency, most characteristics support the speculation strategy for this product. An interesting finding is that, despite common perception that advanced technology products such as mobile telephones favor the postponement strategy, profiling proposes the speculation strategy for this product. Conclusions - Our analysis shows that speculation is not the universal option for supply chain management, and that, when choosing a specific strategy, one should consider many factors simultaneously. A major implication of our work is to emphasize the role of environmental factors such as supply chain variables in choosing an inventory strategy, and the importance of fit rather than solely strategic orientation. A theoretical contribution is to demonstrate the benefit of the simultaneous consideration of business variables in choosing specific strategies. For practitioners, our work leads us to consider the existence and the potential of speculation as a counter-measure to postponement. In addition, the comprehensive framework in this research may be instantly used in examining a practical strategy.

Characterization of the UV Oxidation of Raw Natural Rubber Thin Film Using Image and FT-IR Analysis

  • Kim, Ik-Sik;Lee, Bok-Won;Sohn, Kyung-Suk;Yoon, Joohoe;Lee, Jung-Hun
    • Elastomers and Composites
    • /
    • v.51 no.1
    • /
    • pp.1-9
    • /
    • 2016
  • Characterization of the UV oxidation for raw natural rubber (NR) was investigated in controlled conditions through image and FT-IR analysis. The UV oxidation was performed on a thin film of natural rubber coated on a KBr window at 254 nm and room temperature to exclude the thermal oxidation. Before or after exposure to UV light, image of the NR thin film was observed at a right or tilted angle. FT-IR absorption spectra were measured in transmission mode with the UV irradiation time. The UV oxidation of NR was examined by the changes of absorption peaks at 3425, 1717, 1084, 1477, 1377, and $833cm^{-1}$ which were assigned to hydroxyl group (-OH), carbonyl group (-C=O), carbon-oxygen bond (-C-O), methylene group $(-CH_2-)$, methyl group $(-CH_3)$, and cis-methine group $(cis-CCH_3=CH-)$, respectively. During the initial exposure period, the results indicated that the appearance of carbonyl group was directly related to the reduction of cis-methine group containing carbon-carbon double bond (-C=C-). Most of aldehydes or ketones from carbon-carbon double bonds were formed very fast by chain scission. A lot of long wide cracks with one orientation at regular intervals which resulted in consecutive chain scission were observed by image analysis. During all exposure periods, on the other hand, it was considered that the continuous increment of hydroxyl and carbonyl group was closely related to the decrement of methylene and methyl group in the allylic position. Therefore, two possible mechanisms for the UV oxidation of NR were suggested.

Characterization on the Ozone Oxidation of Raw Natural Rubber Thin Film using Image and FT-IR Analysis

  • Kim, Ik-Sik;Lee, DooYoul;Sohn, Kyung-Suk;Lee, Jung-Hun;Bae, JoongWoo
    • Elastomers and Composites
    • /
    • v.54 no.2
    • /
    • pp.110-117
    • /
    • 2019
  • The characterization of the ozone oxidation for raw natural rubber (NR) was investigated under controlled conditions through image and fourier transform infrared (FT-IR) analysis. The ozone oxidation was performed on a transparent thin film of raw NR coated on a KBr window in a dark chamber at $40^{\circ}C$ under low humidity conditions to completely exclude thermal, moisture, or light oxidation. The ozone concentration was set at 40 parts per hundred million (pphm). Before or after exposure to ozone, the image of the thin film for raw NR was observed at a right or tilted angle. FT-IR absorption spectra were measured in the transmission mode according to ozone exposure time. The ozone oxidation of NR was determined by the changes in the absorption peaks at 1736, 1715, 1697, and $833cm^{-1}$, which were assigned to an aldehyde group (-CHO), a ketone group (-COR), an inter-hydrogen bond between carbonyl group (-C=O) from an aldehyde or a ketone and an amide group (-CONH-) of protein, and a cis-methine group ($is-CCH_3=CH-$, respectively. During ozone exposure period, the results indicated that the formation of the carbonyl group of aldehyde or ketone was directly related to the decrement of the double bond of cis-1,4-polyisoprene. Only carbonyl compounds such as aldehydes or ketones seemed to be formed through chain scission by ozone. Long thin cracks with one orientation at regular intervals, which resulted in consecutive chain scission, were observed by image analysis. Therefore, one possible two-step mechanism for the formation of aldehyde and ketone was suggested.

An Examination of Multi-Dimensional Constructs of Resistance to Supply Chain Management (SCM) Change for a Small and Medium Sized Food Production Company (공급사슬관리 (SCM) 운영 변화의 저항에 영향을 미치는 선행요인 평가 : 식품제조 중소기업 K사 사례를 중심으로)

  • Kim, Dae-Cheol;Kim, Won-Kyo;Seo, Youing-Kyu
    • Journal of Korean Society of Industrial and Systems Engineering
    • /
    • v.42 no.3
    • /
    • pp.206-216
    • /
    • 2019
  • The present study identified several antecedents that create perceived resistance to supply chain management (SCM) change. This work particularly emphasizes SCM change, which is notable given its central role in reacting market orientation and varied environmental and managerial conditions. A careful case study on a small and medium sized food production company in South Korea leads to the formulation of our framework including one second-order construct of 'resistance' as well as eight first-order constructs of 'implementing the payment terms', 'balancing of business process', 'fear of responsibility', 'business sustainability transparency', 'past experience of failure', 'competence of work personnel', 'cooperation with third parties' and 'sharing personnel information with partner'. The hypothesized relation of first- and second-order construct was validated using survey sample data collected from 350 respondents who completed their questionnaire instrument. Results from confirmatory factor analysis revealed that nomological validity was established at statistical significance level by identifying six first order constructs of 'implementing the payment terms', 'fear of responsibility', 'business sustainability transparency', 'past experience of failure', a conbined construct of 'competence of work personnel/cooperation with third parties' and 'sharing personnel information with partner'. The findings from our work are expected to provide important insights to the strategy for SCM risk management for small and medium sized company.

The Effects of Long-Term Relationship Orientation on Green Supply Chain Management and Performance (기업 간 장기적 관계지향성이 그린공급사슬관리와 성과에 미치는 영향)

  • Lee, Seung GI;Kim, Byung-Keun;Park, Young Chan
    • Korean small business review
    • /
    • v.39 no.1
    • /
    • pp.59-87
    • /
    • 2017
  • There is growing concern of the international community for the environmental issues including climate change. Scholars have examined various issues regrading Green Supply Chain Management (GSCM) but they mainly have focused on why firms introduce and implement GSCM from the persecutive of manufacturers. In particular, there has been few studies of green supply chain management in Korea. We investigate the effects of long-term relationships on green supply chain management and the relationship between GSCM and environmental performance. We also examine the relationship between long-term relationships and green information sharing, the effects of green information sharing on the GSCM. The data for this study were collected through a questionnaire survey on firms that participated in the Green Partnership Program of Korea Institute of Industrial Technology. Based on the responses of 155 firms the research model is empirically tested through a structural equation model. We found that long-term relationships facilitate GSCM significantly as it was expected. Green purchase and green product design also appears to improve environmental performance. Long-term relationship appears to affect positively green information sharing. Green information sharing does not have a statistically significant effect on environmental performance but show positive effect on GSCM including green purchase and green product design.