• Title/Summary/Keyword: flow velocity

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Practical Strategies for Urban Regeneration through an Application of Landscape Urbanism (랜드스케이프 어바니즘 관점에서 본 도시재생 전략 연구)

  • Cho, Se-Hwan
    • Journal of the Korean Institute of Landscape Architecture
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    • v.38 no.2
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    • pp.109-118
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    • 2010
  • This study aims to propose practical strategies for the new urban ideal of regeneration. A book review highlights the emergence of new trends of urbanization in knowledge-information industrial society beyond the new town Ideal of the industrial society. The meaning of ‘landscape’ in landscape urbanism represents not the visual and decorative pictures, but the dynamic process in the context of changes and evolutions. Also, knowledge-information industrial society and landscape have a meaning in the same context of flow and process with changes of velocity. Finally, these key words convey a meaning with the new urban trends of urbanization in knowledge-information industrial society in the context of value-oriented characteristics of dynamics and process. Urban regeneration is emerging as the new urban ideal in the knowledge-information industrial society, beyond the new town ideal of industrial society. It is in the same context as landscape urbanism with respect to green infrastructure buildings and designs for the transformation of urban surfaces covered with concrete and asphalt into the ecological surface, and of the ecological surfaces into the cultural surface that could be communicated with human beings. This research revealed the six strategies for urban regeneration as follows. The First, the strategies for the transformation of urban surfaces into ecological surfaces, the second, the strategies for the transformation of ecological surfaces into cultural surfaces, the third, the introduction of mixed and convergence land use, the forth, the transformation of former sites(e.g. military and factory) into urban parks, the fifth, the introduction of waterfront park zones that have the function of ecological and park-oriented mixed land use and, the sixth, the building and design of green infrastructure in the residential and commercial complex in CBD. These strategies call for the reforms of development laws and regulations to restrict building coverage ratio, building heights, and the introduction of park-oriented mixed zoning regulations. Another method for implementating the above listed strategies was the introduction of a strategic planning system instead of the traditional master plan system. This system uses a value planning approach and brand making by imagery. It is able to construct the meaning of an image and its creativeness directly.

A Study on Air Resistance and Greenhouse Gas Emissions of an Ocean Leisure Planning Boat (해양레저용 활주형선의 공기저항 및 온실 가스 배출에 대한 연구)

  • Kim, Y.S.;Hwang, S.K.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.16 no.3
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    • pp.202-210
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    • 2013
  • As incomes increase, interest in ocean leisure picks up. As a result, a lot of research and developments on hull form design and production of planing boats, mostly used for ocean leisure, are needed. Analysis in researches on resistance of planing boats shows that resistance characteristic of planing boats is different from resistance characteristic of general boats because the former is fast, and its wetted surface is very small. Using Savitsky formula widely used in the calculation of effective horse power in shipbuildingyards, and propulsion system and engine manufacturers, this study calculated total resistance of a research planing boat. Then it analyzed the flow characteristics of the planing boat through theoretical analysis and wind tunnel experiment, and computed air resistance and lift force by changes of speed and trim angle. It also compared and analyzed result of theoretical analysis and experiment of the ratio of air resistance to total resistance under variations of velocity and trim angle. When the study is used to estimate more accurate effective horse power, it is expected to remedy abuses of unnecessarily installing high-powered engine. As nature disasters due to abnormal changes of weather increase, interest in greenhouse gas grows. International Maritime Organization (IMO) legislated Energy Efficiency Design Index (EEDI) and Energy Efficiency Operational Indicator (EEOI) to reduce ship greenhouse gas emissions. But this index will be applied to over 400 tons ships, small ships, emitting more greenhouse gases than larege ships per unit power, will dodge the regulations. Thus, this study indicated a problem by calculating greenhouse gas emissions of an ocean leisure planning boat (a small ship), and suggested the need for EEDI of small ships.

Effect of Self-Myofascial Release on Body Composition, Vascular and Metabolic Functions in Obese Female College Students (자가근막이완 운동이 비만 여자대학생의 신체조성과 혈관 및 대사기능에 미치는 효과)

  • Lee, Jae-Hoon;Kim, Ji-Sun;Oh, Yoo-Seong
    • Journal of the Korean Applied Science and Technology
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    • v.37 no.4
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    • pp.769-777
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    • 2020
  • The purpose of this study was to investigate the effects of 8 weeks Self-Myofascial Release exercise on body composition, vascular and metabolic functions in obese female college students. The subjects were 19 obese female college students (n = 9) who were randomly assigned to an exercise group(n=9) and control group(n=9), with an exception of except 1 abandonment. The Self-Myofascial Release exercise group performed exercises twice a week for 8 weeks and for 40 minutes at one time using a foam roller, and the control group maintained normal life pattern for the same period. Body composition was measured by body weight, body fat percentage, vascular function was measured by pulse wave velocity(PWV), augmentation index(AIx), brachial artery vascular flow-mediated dilation(FMD), and metabolic function was measured by fasting glucose and triglyceride levels. The Self-Myofascial Release exercise with foam roller showed no significant effect on body weight and body fat percentage. The Self-Myofascial Release exercise with foam roller showed no significant effect on heart rate, FMD, PWV but, SBP, CSBP and AIx were significant decreased. The Self-Myofascial Release exercise with foam roller showed no significant effect on fasting glucose and triglyceride levels. In conclusion, 8-week Self-Myofascial Release exercise for obese female college students showed no significant effect on body composition and metabolic function, but improved SBP, CSBP and AIx levels significantly. Therefore, Self-Myofascial Release exercise will be an effective way to improve the vascular function of obese female college students.

Heterogeneous Oxidation of Liquid-phase TCE over $CoO_x/TiO_2$ Catalysts (액상 TCE 제거반응을 위한 $CoO_x/TiO_2$ 촉매)

  • Kim, Moon-Hyeon;Choo, Kwang-Ho
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.3
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    • pp.253-261
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    • 2005
  • Catalytic wet oxidation of ppm levels of trichloroethylene (TCE) in water has been conducted using $TiO_2$-supported cobalt oxides at a given temperature and weight hourly space velocity. 5% $CoO_x/TiO_2$ might be the most promising catalyst for the wet oxidation at $36^{\circ}C$ although it exhibited a transient behavior in time on-stream activity. Not only could the bare support be inactive for the wet decomposition reaction, but no TCE removal also occurred by the process of adsorption on $TiO_2$ surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. Characterization of the $CoO_x$ catalyst by acquiring XPS spectra of both fresh and used Co surfaces gave different surface spectral features of each $CoO_x$. Co $2p_{3/2}$ binding energy of Co species exposed predominantly onto the outermost surface of the fresh catalyst appeared at 781.3 eV, which is very similar to the chemical states of $CoTiO_x$ such as $Co_2TiO_4$ and $CoTiO_3$. The spent catalyst possessed a 780.3 eV main peak with a satellite structure at 795.8 eV. Based on XPS spectra of reference Co compound, the TCE-exposed Co surfaces could be assigned to be in the form of mainly $Co_3O_4$. XRD measurements indicated that the phase structure of Co species in 5% $CoO_x/TiO_2$ catalyst even before reaction is quite comparable to the diffraction lines of external $Co_3O_4$ standard. A model structure of $CoO_x$ present on titania surfaces would be $Co_3O_4$, encapsulated in thin-film $CoTiO_x$ species consisting of $Co_2TiO_4$ and $CoTiO_3$, which may be active for the decomposition of TCE in a flow of water.

Relationship between Distribution of the Dominant Phytoplankton Species and Water Temperature in the Nakdong River, Korea (낙동강의 식물플랑크톤 우점종의 분포특성 및 수온과의 상관성)

  • Yu, Jae Jeong;Lee, Hye Jin;Lee, Kyung Lak;Lyu, Heuy Seong;Whang, Jeong Wha;Shin, La Young;Chen, Se Uk
    • Korean Journal of Ecology and Environment
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    • v.47 no.4
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    • pp.247-257
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    • 2014
  • The construction of eight large weirs in the Nakdong River, Korea, caused a decrease in the water flow velocity and several physical changes to the water environment. Here, changes in phyto- and zooplankton communities and water quality in the areas near the eight weirs were investigated from 2011 to 2013, and relationships between phytoplankton abundances and environmental factors were analyzed. Special emphasis was given to the succession patterns in algal abundance based on temperature fluctuations. At the eight weirs, 24 dominant species were found. The most abundant phytoplankton species was Stephanodiscus sp. (39.4% of dominant frequency). Cyanobacteria of the genus Microcystis dominated during the summer, with an dominant frequency of 8.5% and cell abundance ratio of 36.6%. Significant correlations were observed between temperature and abundance of eight of the main dominant species; seven species showed positive correlations with temperature. Stephanodiscus sp., however, showed a negative correlation with temperature (r=-0.26, p<0.01). In addition, this species showed a significant negative correlation with the dominant algal species-Aulacoseira granulata and Aphanizomenon flos-aquae, with the zooplankton Copepoda and with Cladocera. On the contrary, seven other dominant species of algae showed significant positive correlations with zooplankton. Thus, we showed that the seasonal succession of plankton communities in the Nakdong River was related to the water temperature changes.

Characteristics of Pd Catalysts for Methane Oxidation (메탄 산화를 위한 Pd 촉매의 특성)

  • Lee, Jin-Man;Yang, O-Bong;Kim, Chun-Yeong;Woo, Seong-Ihl
    • Applied Chemistry for Engineering
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    • v.10 no.4
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    • pp.557-562
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    • 1999
  • The reaction properties of Pd. Pd-Ce and Pd-La catalysts supported on ${\gamma}-Al_2O_3$ were investigated in the oxidation reaction of methane($CH_4$) exhausted from the compressed natural gas vehicle in a U-tube flow reactor with gas hourly space velocity of $72,000h^{-1}$. The catalysts were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), BET surface area and hydrogen chemisorption. Pd catalyst prepared by $Pd(NO_3)_2$ as a palladium precursor and calcined at $600^{\circ}C$ showed the highest activity for a methane oxidation. Catalytic activity of calcined $Pd/{\gamma}-Al_2O_3$ in which most of palladium was converted into palladium oxide species was higher than that of reduced $Pd/{\gamma}-Al_2O_3$ in which most of palladium existed in palladium metal by XRD. As increasing the number of reaction cycles in the wide range of redox, the catalytic activity of $Pd/{\gamma}-Al_2O_3$ was decreased and the highly active window became narrower. Lanthanum oxide promoted Pd catalyst, $Pd/La/{\gamma}-Al_2O_3$ showed enhanced thermal stability compared with $Pd/{\gamma}-Al_2O_3$ even after aging at $1000^{\circ}C$, which was ascribed to the role of La as a promoter to suppress the sintering of palladium metal and ${\gamma}-Al_2O_3$ support. Almost all of methane was removed by the reaction with NO at the redox ratio of 1.2 in case of oxygen excluded steam, but that activity was significantly decreased in the steam containing oxygen.

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COMPARISON OF FLUX AND RESIDENT CONCENTRATION BREAKTHROUGH CURVES IN STRUCTURED SOIL COLUMNS (구조토양에서의 침출수와 잔존수농도의 파과곡선에 관한 비교연구)

  • Kim, Dong-Ju
    • Journal of Korea Soil Environment Society
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    • v.2 no.2
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    • pp.81-94
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    • 1997
  • In many solute transport studies, either flux or resident concentration has been used. Choice of the concentration mode was dependent on the monitoring device in solute displacement experiments. It has been accepted that no priority exists in the selection of concentration mode in the study of solute transport. It would be questionable, however, to accept the equivalency in the solute transport parameters between flux and resident concentrations in structured soils exhibiting preferential movement of solute. In this study, we investigate how they differ in the monitored breakthrough curves (BTCs) and transport parameters for a given boundary and flow condition by performing solute displacement experiments on a number of undisturbed soil columns. Both flux and resident concentrations have been simultaneously obtained by monitoring the effluent and resistance of the horizontally-positioned TDR probes. Two different solute transport models namely, convection-dispersion equation (CDE) and convective lognormal transfer function (CLT) models, were fitted to the observed breakthrough data in order to quantify the difference between two concentration modes. The study reveals that soil columns having relatively high flux densities exhibited great differences in the degree of peak concentration and travel time of peak between flux and resident concentrations. The peak concentration in flux mode was several times higher than that in resident one. Accordingly, the estimated parameters of flux mode differed greatly from those of resident mode and the difference was more pronounced in CDE than CLT model. Especially in CDE model, the parameters of flux mode were much higher than those of resident mode. This was mainly due to the bypassing of solute through soil macropores and failure of the equilibrium CDE model to adequate description of solute transport in studied soils. In the domain of the relationship between the ratio of hydrodynamic dispersion to molecular diffusion and the peclet number, both concentrations fall on a zone of predominant mechanical dispersion. However, it appears that more molecular diffusion contributes to the solute spreading in the matrix region than the macropore region due to the nonliearity present in the pore water velocity and dispersion coefficient relationship.

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Fundamental Studies on the Development of Axial-Flow Combine(I) -Evaluation of the Design Parameters of Grain-Straw Separator- (축류(軸流) 콤바인의 개발(開發)에 관(關)한 기초(基礎) 연구(硏究)(I) -조선별장치(粗選別裝置)의 설계변수(設計變數)의 평가(評價)-)

  • Lee, S.K.;Kim, S.T.;Choi, K.H.
    • Journal of Biosystems Engineering
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    • v.11 no.2
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    • pp.31-40
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    • 1986
  • Cylindrical and conical types of grain-straw separation equipment which has a stationary crimped sieve drum with rotating inner rotor were constructed. The developed equipments were tested to investigate the characteristics of separating performance under various mechanical conditions and crop conditions. As increase of the inclination of equipment and decrease of pitch of cover vane, the grain recovery was increased while straw rejection was decreased. The grain recovery and overall efficiency were decreased as the rotor speed and feeding velocity were increased for both varieties of rice, moisture contents, and test equipments. Conical prototype equipment performed higher straw rejection, lower grain recovery, and lower power requirement. However, separation performance of conical type equipment was more widely varied with various test conditions compared to cylindrical one. The performance of both equipments showed relatively insensitive to crop feedrate and crop properties, such as variety, moisture content, and grain-to-straw ratio.

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The Electrochemical Chlorination for Marine Plankton Community Disinfection (해양 플랑크톤 군집의 전기분해 염소소독 효과)

  • Kang, Jung-Hoon;Shin, Kyoung-Soon;Hyun, Bong-Gil;Jang, Min-Chul;Kim, Eun-Chan;Chang, Man
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.10 no.3
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    • pp.127-137
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    • 2007
  • To confirm whether or not the Electrochemical Disinfection System (EDS) meet with the D-2 regulation established by IMO (International Maritime Organization), the biological treatment efficacy of the EDS was assessed using three groups of natural marine plankton (bacteria, $10-50\;{\mu}m$ and $>50\;{\mu}m$ sized organisms). Influent water was passed through the EDS under the flow velocity ($23.8\;m^3/hr$) and test design was consisted of control (no treatment) and experimental (10 ppm and 30 ppm) condition for total residual chlorine (TRC). And the biological condition of the influent water followed the standards established by the guidelines for the approval of ballast water management systems. The disinfection efficacy of the $10-50\;{\mu}m$ sized organisms (phytoplankton) was assessed by three kinds of measurements using photomicroscope, epifluorescence microscope and fluorometer (fumer Designs 10-AU). After being passed through the EDS, all motile phytoplankton lost their motility under photomicroscope, the colour of chlorophyll fluorescence fumed from red into green under epifluorescence, and the high chlorophyll fluorescence (Expt. 1: 6.95, Expt. 2: 7.11) detected by fluorometer decreased into value not detected. These results indicated phytoplankton community was totally killed after electrochemical disinfection treatment. Survivorship of the larger organisms than $50\;{\mu}m$ was determined based on the appendage's movement under a stereomicroscope. Natural assemblage collected from ambient seawater was killed shortly after being passed through the EDS, whereas some Artemia remained alive. However, no live Artemia was found after 24 hour further exposure to each TRC concentration (10 and 30 ppm) under darkness. After electrochemical treatment, the target bacteria such as aerobes, coliform and Escherichia coli were completely killed on the basis of CFU (colony forming unit) on Petrifilm plate ($3\;M^{TM}$) after 48 hr incubation. Moreover, no regrowth was found in the three groups of plankton during five days under additional exposure to the treated water. These results indicated that the disinfection efficiency of the EDS on the three groups of plankton satisfy D-2 regulation.

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An Association of Changed Levels of Inflammatory Markers with Hematological Factors during One-time Aerobic Exercise in Twenty-aged Young Men (20대 젊은이들에 있어 1회성 유산소운동 시 염증 표지자와 혈액변인들 간의 상관관계)

  • Hyun, Kyung-Yae
    • Journal of Life Science
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    • v.19 no.11
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    • pp.1658-1665
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    • 2009
  • This study was carried out on thirty men to define the association of inflammatory markers with physiological factors on one-time aerobic exercise (for 15 min. Post-exercise interleukin-6 (IL-6), mean corpuscular hemoglobin concentration (MCHC), heart rate (HR), systolic blood pressure (SBP), and pulsatility and resistance index of middle cerebral artery (PI and RI, respectively) levels were elevated compared to those measured pre-exercise. Total leukocyte and platelet counts, high-sensitivity C-reactive protein (hs-CRP), free radical (FR), and low density lipoprotein cholesterol (LDL) levels tended to decrease after exercise. Pre-exercise IL-6 levels were positively correlated with pre-exercise SBP levels, while post-exercise IL-6 level was positively correlated with post-exercise PI and RI levels. Post-exercise, hs-CRP levels were negatively related to SBP and HR. Pre-exercise, FR levels were positively associated to SBP, DBP, and HR. Post-exercise FR levels were negatively related to the post-exercise blood flow velocity in middle cerebral artery. Pre-exercise erythrocyte indices (RBC, MCV, MCH, and MCHC levels) were in inverse proportion to pre-exercise IL-6 levels. Post-exercise FR levels were inversely related to post-exercise total leukocyte, lymphocyte, monocyte, and MCH levels. Pre-exercise $Mg^{++}$ levels were in inverse proportion to pre-exercise IL-6, hs-CRP, or FR levels. These findings suggest that one-time aerobic exercise offers a significant relationship between inflammatory markers and some biochemical markers or electrolytes. Further studies need to be carried out for investigation of differences between genders or age groups following one-time or regular aerobic exercise.