• Title/Summary/Keyword: well diffusion

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Removals of Formaldehyde by Silver Nano Particles Attached on the Surface of Activated Carbon (나노 은입자가 첨착된 활성탄의 포름알데히드 제거특성)

  • Shin, Seung-Kyu;Kang, Jeong-Hee;Song, Ji-Hyeon
    • Journal of Korean Society of Environmental Engineers
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    • v.32 no.10
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    • pp.936-941
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    • 2010
  • This study was conducted to investigate formaldehyde removals by silver nano-particles attached on the surface of granular activated carbon (Ag-AC) and to compare the results to those obtained with ordinary activated carbon (AC). The BET analysis showed that the overall surface area and the fraction of micropores (less than $20{\AA}$ diameter) of the Ag-AC were significantly decreased because the silver particles blocked the small pores on the surface of the Ag-AC. The formaldehyde removal capacity of the Ag-AC determined using the Freundlich isotherm was higher than that of AC. Despite the decreased BET surface area and micropore volume, the Ag-AC had the increased removal capacity for formaldehyde, presumably due to catalytic oxidation by silver nano-particles. In contrast, the adsorption intensity of the Ag-AC, estimated by 1/n in the Freundlich isotherm equation, was similar to that of the ordinary AC, indicating that the surface modification using silver nano-particles did not affect the adsorption characteristics of AC. In a column experiment, the Ag-AC also showed a longer breakthrough time than that of the AC. Simulation results using the homogeneous surface diffusion model (HSDM) were well fitted to the breakthrough curve of formaldehyde for the ordinary AC, but the predictions showed substantial deviations from the experimental data for the Ag-AC. The discrepancy was due to the catalytic oxidation of silver nano-particles that was not incorporated in the HSDM. Consequently, a new numerical model that takes the catalytic oxidation into accounts needs to be developed to predict the combined oxidation and adsorption process more accurately.

Fracture and Hygrothermal Effects in Composite Materials (복합재의 파괴와 hygrothermal 효과에 관한 연구)

  • Kook-Chan Ahn;Nam-Kyung Kim
    • Journal of the Korean Society of Safety
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    • v.11 no.4
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    • pp.143-150
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    • 1996
  • This is an explicit-Implicit, finite element analysis for linear as well as nonlinear hygrothermal stress problems. Additional features, such as moisture diffusion equation, crack element and virtual crack extension(VCE ) method for evaluating J-integral are implemented in this program. The Linear Elastic Fracture Mechanics(LEFM) Theory is employed to estimate the crack driving force under the transient condition for and existing crack. Pores in materials are assumed to be saturated with moisture in the liquid form at the room temperature, which may vaporize as the temperature increases. The vaporization effects on the crack driving force are also studied. The Ideal gas equation is employed to estimate the thermodynamic pressure due to vaporization at each time step after solving basic nodal values. A set of field equations governing the time dependent response of porous media are derived from balance laws based on the mixture theory Darcy's law Is assumed for the fluid flow through the porous media. Perzyna's viscoplastic model incorporating the Von-Mises yield criterion are implemented. The Green-Naghdi stress rate is used for the invariant of stress tensor under superposed rigid body motion. Isotropic elements are used for the spatial discretization and an iterative scheme based on the full newton-Raphson method is used for solving the nonlinear governing equations.

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Sectoral Patterns of Technological Innovation in Korean Manufacturing Sector (한국 제조업의 산업별 기술혁신패턴 분석)

  • Hong, Jang-Pyo;Kim, Eun-Young
    • Journal of Technology Innovation
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    • v.17 no.2
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    • pp.25-53
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    • 2009
  • The purpose of this paper is to analysis sectoral patterns of technological innovation in Korean manufacturing sector. Pavitt(1984) put forward a well-known taxonomy that industries three groups of industries characterized by markedly different innovative modes, namely science-based, production-intensive and supplier-dominated industries. Using Pavitt's taxonomy as a framework, we try to explain similarities and differences among sectors in the sources and impact of innovations. Based on a sample of 2,371 firms in manufacturing industry, this paper investigated its relevance to explain the sources and directions of innovative activities in Korean industries. Empirical study shows that in supplier dominated firms most process innovations come from suppliers of equipment and materials. In science-based firms product innovation is produced internally, based on the rapid development of the underlying sciences in the universities and research institutes. It also shows that production-intensive firms have a positive association between innovativeness and customer collaboration. This explanation has implications for our understanding of the sources and directions of technical changes, the formation of technological advantages at the level of both region and country.

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Application Potential of Hurdle Technology by Combination of Bacteriocin Produced by Lactobacillus brevis DK25 and Potassium Benzoate (Lactobacillus brevis DK25의 박테리오신과 안식향산칼륨과의 혼용에 의한 Hurdle Technology 적용 가능성)

  • Lim, Sung-Mee
    • Korean Journal of Microbiology
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    • v.47 no.4
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    • pp.364-374
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    • 2011
  • Lactobacillus brevis DK25 isolated from Dongchimi was identified by physiological and biochemical tests and 16S rDNA sequence analysis. Bacteriocin of L. brevis DK25 exhibits inhibitory activity against Enterococcus faecalis and Listeria monocytogenes when using agar well diffusion method. Maximal production of bacteriocin was reached in the beginning of the stationary phase, and inhibitory activity declined after the late stationary phase. This result suggested that bacteriocin was produced in a growth-associated manner. Complete inactivation of bacteriocin activity was observed after treatment with protease, but the activity was stable between pH 4-9 and heat resistant (30 min at $100^{\circ}C$). Bacteriocin showed a concentration-dependent antimicrobial activity against L. monocytogenes KCTC 3569. Moreover, the application experiment showed that combination of bacteriocin (320 AU/ml) with potassium benzoate (0.05%) could significantly reduce the counts of L. monocytogenes KCTC 3569 in mayonnaise during storage at 4 or $25^{\circ}C$ for 10 days. Thus, bacteriocin from L. brevis DK25 may be used for hurdle technology by combination with potassium benzoate in order to increase pathogenic bacteria inactivation in food processing and food safety control.

Bioequivalence of Two Clarithromycin Tablets (클래리스로마애신 정제의 생물학적 동등성 평가)

  • 김종국;이사원;최하곤;고종호;이미경;김인숙
    • Biomolecules & Therapeutics
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    • v.6 no.2
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    • pp.219-224
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    • 1998
  • The bioequivalence of two clarithromvcin products was evaluated with 16 normal male volunteers (age 23-28 yr, body weight 57.5-75.517g) following single oral dose. Test product was ReYon Clarithromycin tablets (ReYon Pharm. Corp., Korea) and reference product was Klarici $d_{R}$ tablets (Abbott Korea). Both products contain 250 mg of clarithromucin. One tablet of the test or the reference product was administered to the volunteers, respectively, by randomized two period cross-over study (2$\times$2 Latin square method). The determination of clarithromycin was accomplished using a modified agar well diffusion bioassay. As a result of the assay validation, the quantification of clarithromycin in human serum by this technique was possible down to 0.03$\mu$g/ml using 100$\mu$l of serum. The coefficient of variation (C.V.) was less than 10%. Average drug concentrations at each sampling time and pharmacokinetic parameters calculated were not significantly different between two products P>0.05); the area under the curve to last sampling time (24 hr) (AU $Co_{24hr}$ (8.10$\pm$ 1.26 vs 8.22$\pm$ 1.627g . hr/ml), AUC from time zero to infinite (AU $Co_{\infty}$) (8.61 $\pm$ 1.28 vs 8.84$\pm$ 1.71 $\mu$g . hr/ml), maximum plasma concentration ( $C_{msx}$) (0.87$\pm$0.22 vs 0.88$\pm$0.19 $\mu$g/ml) and time to maximum plasma concentration ( $T_{max}$) (2.69 $\pm$0.48 vs 2.56$\pm$ 0.51 hr). The differences of mean AU $Co_{24h}$, $C_{msx}$ and $T_{msx}$ between the two products (1.44, 1.39, and 4.65%, respectively) were less than 20%. The power (1-$\beta$) and treatment difference ($\Delta$) for AU $Co_{24hr}$, and $C_{max}$ were more than 0.8 and less than 0.2, respectivly. Although the power for $T_{max}$ was under 0.8, $T_{max}$. of the two products was not significantly different each other (p>0.05). These results suggest that the bioavailability of ReYon Clarithromycin tablets is not significantly different from that of Klarici $d_{R}$ tablets. Therefore, two products are bioequivalent based on the current results. results.sults.sults.s.s.s.s.s.s.s.

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$TiO_2$-Encapsulated EFAL-Removed Zeolite Y as a New Photocatalyst for Photodegradation of Azo Dyes in Aqueous Solution

  • ChO, Won-Je;Sook-Ja Yoon,;Yoon, Min-Joong
    • Journal of Photoscience
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    • v.12 no.1
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    • pp.17-23
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    • 2005
  • Application of a new photocatalyst has been attempted to improve the efficiency and rates of photocatalytic degradation of azo dyes by using a model dye such as Methyl Orange. As a new photocatalyst, $TiO_2$ encapsulated EFAL-removed zeolite Y ($TiO_2$ /EFAL-removed zeolite Y) has been synthesized by ion-exchange in the mixture of EFAL-removed zeolite Y with 0.05 M aqueous [$(NH_4)_2 TiO(C_2O_4)_2.H_2O$] [$TiO(C_2O_4)_2.H_2O$]. This new photocatalyst has been characterized by measuring XRD, IR and reflectance absorption spectra as well as ICP analysis, and it was found that the framework structure of $TiO_2$ /EFAL-removed zeolite Y is not changed by removing the extra-framework aluminum (EFAL) from the normal zeolite Y and the $TiO_2$ inside the photocatalyst exists in the form of $(TiO^{2+})_n$ nanoclusters. Based on the ICP analysis, the Si/Al ratio of the $TiO_2$ /EFAL-removed zeolite Y and the weight of $TiO_2$ were determined to be 23 and 0.061g in 1.0g photocatalyst, respectively. It was also found that adsorption of the azo dye in the $TiO_2$ /EFAL-removed zeolite is very effective (about 80 % of the substrate used). This efficient adsorption contributes to the synergistic photocatalytic activities of the $TiO_2$ /EFAL-removed zeolite by minimizing the required flux diffusion of the substrate. Thus, the photocatalytic reduction of methyl orange (MO) was found to be 8 times more effective in the presence of $TiO_2$ /EFAL-removed zeolite Y than in the presence of $TiO_2$ /normal zeolite Y. Furthermore, the photocatalytic reduction of MO by using 1.0 g of the $TiO_2$ /EFAL-removed zeolite Y containing 0.061g of $TiO_2$ is much faster than that carried out by using 1.0 g of Degussa P-25.

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Developing a Roadmap for National Research Data Management Governance: Based on the Analysis of United Kingdom's Case (국가 차원의 연구데이터 관리체계 구축을 위한 로드맵 제안 - 영국 사례 분석을 중심으로 -)

  • Shim, Wonsik
    • Journal of the Korean Society for Library and Information Science
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    • v.49 no.4
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    • pp.355-378
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    • 2015
  • In recent years, countries such as USA, United Kingdom and Australia have begun to implement national policies in order to systematically manage and share research data produced through publicly funded research. However, Korea as of yet does not have a coordinated research data policy. The lack of infrastructure that supports the sharing and preserving research data results in the poor management and loss of valuable data produced from significant national R&D investments. The need for research data collection, management and sharing goes beyond the outcome assessment of national research: it facilitates the diffusion of research impact and economic development. There is a growing recognition that data sharing is an essential element of research ethics. This research investigates the relevant research data policies and methods of governance at the national level using a case study analysis. United Kingdom was selected as a case study target as it shows a wide variety of policy examples and instruments. In particular, this research focuses on the UK's national legal framework for research data sharing, analyzes the RCUK (Research Councils UK)'s data policies, activities at the seven research councils under RCUK as well as several supporting institutions. Based on the analyses, this research offers a national roadmap for better managing and sharing of research data in Korea.

Analysis of Density Current in the Tidal River (감조하천(感潮河川)의 하구(河口) 밀도류해석(密度流解析))

  • Suh, Seung Duk;Park, Sung Bae
    • Current Research on Agriculture and Life Sciences
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    • v.4
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    • pp.70-76
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    • 1986
  • The purpose of this study is to offer the basic data of the tidal river development program by grasping the diffusion between the high density-sea water and the low density-fresh water in the tidal river. The tidal range of Hyungsan river which flows at Youngil bay in Pohang was selected to analysis the phenomenon of density current. The results obtained are as follows ; The tide of Youngil bay was one time a day, 0.104m in high tide difference and 0.085m in mean tidy difference. The change of sea level by tide was negligible. The volume of reserved water by sea water was $2,700,000m^3$ and available water of irrigation was $1,200,000m^3$ that salt density is below $750{\mu}{\mho}/cm$ out of total volume. Salt intrusion phenomenon by density current was a little water level change, however, it become a salt wedge type by the much salt invasion during the spring tide and it makes a well-mixed type by the retreating salt wedge during the neap tide. As long as there were some density differences between sea water and fresh water, net upstream flow was existed along the bottom of water way from the estuary to the upstream channel.

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Memory-Free Skin-Detection Algorithm and Implementation of Hardware Design for Small-Sized Display Device (소형 DISPLAY 장치를 위한 비 메모리 피부 검출 알고리즘 및 HARDWARE 구현)

  • Im, Jeong-Uk;Song, Jin-Gun;Ha, Joo-Young;Kang, Bong-Soon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.8
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    • pp.1456-1464
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    • 2007
  • The research of skin-tone detection has been conducting continuously to enlarge the importance in security, surveillance and administration of the information and 'Password Control System' for using face and skin recognition in airports, harbors and general companies. As well as tile rapid diffusion of the application range in image communications and an electron transaction using wide range of communication network, the importance of the accurate detection of skin color has been augmenting recently. In this paper, it will set up the boundaries of skin colors using the information of Cb and Cr in YCbCr color model of human skin color which is from hundreds compiled portrait images for each race, and suggest a efficient yet simple structure about the skin detection which has been followed by whether the comprehension of the boundaries of skin or not with adaptive skin-range set. With the possibility of the 1D Processes which does not use any memory, it is able to be applied to relatively small-sized hardware and system such as mobile apparatuses. To add the selective mode, it is not only available the improvement of tie skin detection, but also showing the correspondent results about previous face recognition technologies using complicated algorithm.

Artists or Educators? : A Phenomenological Study on the Collective Identity of Future Arts & Culture Education Instructors (ACEIs) (예술가인가 교육가인가?: 문화예술교육사 국가자격증 취득희망자의 정체성에 관한 현상학적 연구)

  • Kim, InSul;Park, ChilSoon;Cho, Hyojung
    • Review of Culture and Economy
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    • v.17 no.2
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    • pp.185-216
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    • 2014
  • It has been two years since the national certificate of Arts & Culture Education Instructor(ACEI) was implemented the 2012 amendment to the Arts & Culture Education Act. Separate from the initial policy goals, students who attend the program to achieve ACEI certificate share various expectations, motivations and intents. The purpose of the research is to understand the collective identity of future ACEIs to evaluate the initial policy implementation during the period when the collective professional identity has not been fully formed yet. This research studies the data that were collected from 172 students who were attending one of the official ACEI institutes in Seoul area. As one of qualitative research methods, Questionnaire Method was employed to conduct this phenomenological study. James E Marcia's theory provides the theoretical framework for the data analysis of this study. The research results indicate that many students'identity status are between Identity Diffusion and Moratorium, which raises concerns for both arts and cultural fields as well as the policy success. Therefore, this research will relate these findings to the larger arts and culture infrastructure in order to better prepare them as arts and cultural professionals and also to stress the importance of the job market development and social environment that can accept them.