• Journal of Soil and Groundwater Environment
• /
• v.18 no.3
• /
• pp.109-118
• /
• 2013

Characteristics of the transport of zero-valent iron nanoparticles (nZVI) in an aquifer were investigated to evaluate an application of nZVI-based reactive zone technology. Main flow direction of groundwater was north. Preferential flow paths of the groundwater identified by natural gradient tracer test were shown northeast and northwest. The highest groundwater velocity was $4.86{\times}10^{-5}$ m/s toward northwest. When the breakthrough curves obtained from the gravity injection of nZVI were compared with the tracer curves, the transport of nZVI was retarded and retardation factors were 1.17 and 1.34 at monitoring wells located on the northeast and northwest, respectively. The ratios of the amount of nZVI delivered to the amount of tracer delivered at the two wells mentioned above were 24 and 28 times greater than that of the well on the main flow direction, respectively. Attachment efficiency based on a filtration theory was $4.08{\times}10^{-2}$ along the northwest direction that was the main migration route of nZVI. Our results, compared to attachment efficiencies obtained in other studies, demonstrate that the mobility of nZVI was higher than that of results reported in previous studies, regardless of large iron particle sizes of the current study. Based on distribution of nZVI estimated by the attachment efficiency, it was found that nZVI present within 1.05 m from injection well could remove 99% of TCE within 6 months.

• Bulletin of the Korean Mathematical Society
• /
• v.50 no.1
• /
• pp.37-56
• /
• 2013

This paper deals with the behavior of positive solutions to the following nonlocal polytropic filtration system $$\{u_t=(\mid(u^{m_1})_x{\mid}^{{p_1}^{-1}}(u^{m_1})_x)_x+u^{l_{11}}{{\int_0}^a}v^{l_{12}}({\xi},t)d{\xi},\;(x,t)\;in\;[0,a]{\times}(0,T),\\{v_t=(\mid(v^{m_2})_x{\mid}^{{p_2}^{-1}}(v^{m_2})_x)_x+v^{l_{22}}{{\int_0}^a}u^{l_{21}}({\xi},t)d{\xi},\;(x,t)\;in\;[0,a]{\times}(0,T)}$$ with nonlinear boundary conditions $u_x{\mid}{_{x=0}}=0$, $u_x{\mid}{_{x=a}}=u^{q_{11}}u^{q_{12}}{\mid}{_{x=a}}$, $v_x{\mid}{_{x=0}}=0$, $v_x|{_{x=a}}=u^{q21}v^{q22}|{_{x=a}}$ and the initial data ($u_0$, $v_0$), where $m_1$, $m_2{\geq}1$, $p_1$, $p_2$ > 1, $l_{11}$, $l_{12}$, $l_{21}$, $l_{22}$, $q_{11}$, $q_{12}$, $q_{21}$, $q_{22}$ > 0. Under appropriate hypotheses, the authors establish local theory of the solutions by a regularization method and prove that the solution either exists globally or blows up in finite time by using a comparison principle.

• Current Research on Agriculture and Life Sciences
• /
• v.33 no.1
• /
• pp.19-24
• /
• 2015

Due to various environmental changes, the current location of the Gyeongsangbuk-do Agricultural Research & Extension Services needs to be changed to provide an appropriate environment and ecosystem for agricultural research and the efficient provision of public services. Accordingly, this study proposes a standard for selecting the new location. First, the location theory for the transfer of public facilities is investigated, and candidate filtration methods considered for the location selection. The candidate filtration methods include a component inspection, branch shape analysis, and mixed analysis. This study uses a component inspection, where the component criteria include the economic feasibility and ease of development, accessibility and convenience, agricultural conditions, soil conditions, connectivity, fairness, and human resource-richness of the region.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.12 no.2
• /
• pp.285-291
• /
• 1992

The purpose of this research, through kinetic analyses and pilot plant experimentation of biofilm filtration reactor, is to study the theoretical equation of head loss in the Biofilm Reactor. The Head loss in the biofilm reactor has occurred due to the biofilm growth and the adhesion to the media surface and stagnation of upflow air bubble, which have caused the pore spaces to become smaller. On a basis of the head loss theory of sand filtration, therefore, the following equation of head loss for the biofilm reactor was proposed from this research results and proved to be possible to apply the equation for practical design of the biofilm filter. $h={\frac{h_o}{L}}{\int}^L_00.58\exp[-4.5){\sigma}_B)][{\frac{1-{\varepsilon}_o+({\sigma}_B)}{1-{\varepsilon}_o}}]^2{[\frac{{\varepsilon}_o}{{\varepsilon}_o-({{\varepsilon}_B)}}]^3dz$ here ${\sigma}_B=0.130+0.001{\theta}$.

• Korean Membrane Journal
• /
• v.7 no.1
• /
• pp.1-18
• /
• 2005

The permeate flux decline due to membrane fouling can be addressed using a variety of theoretical stand-points. Judicious selection of an appropriate theory is a key toward successful prediction of the permeate flux. The essential criterion f3r such a decision appears to be a detailed characterization of the feed solution and membrane properties. Modem theories are capable of accurately predicting several properties of colloidal systems that are important in membrane separation processes from fundamental information pertaining to the particle size, charge, and solution ionic strength. Based on such information, it is relatively straight-forward to determine the properties of the concentrated colloidal dispersion in a polarized layer or the cake layer properties. Incorporation of such information in the framework of the standard theories of membrane filtration, namely, the convective diffusion equation coupled with an appropriate permeate transport model, can lead to reasonably accurate prediction of the permeate flux due to colloidal fouling. The schematic of the essential approach has been delineated in Figure 5. The modern approaches based on appropriate cell models appear to predict the permeate flux behavior in crossflow membrane filtration processes quite accurately without invoking novel theoretical descriptions of particle back transport mechanisms or depending on adjust-able parameters. Such agreements have been observed for a wide range of particle size ranging from small proteins like BSA (diameter ${\~}$6 nm) to latex suspensions (diameter ${\~}1\;{\mu}m$). There we, however, several areas that need further exploration. Some of these include: 1) A clear mechanistic description of the cake formation mechanisms that clearly identifies the disorder to order transition point in different colloidal systems. 2) Determining the structure of a cake layer based on the interparticle and hydrodynamic interactions instead of assuming a fixed geometrical structure on the basis of cell models. 3) Performing well controlled experiments where the cake deposition mechanism can be observed for small colloidal particles (< $1\;{\mu}m$). 4) A clear mechanistic description of the critical operating conditions (for instance, critical pressure) which can minimize the propensity of colloidal membrane fluting. 5) Developing theoretical approaches to account for polydisperse systems that can render the models capable of handing realistic feed solutions typically encountered in diverse applications of membrane filtration.

• The Journal of the Korea Contents Association
• /
• v.5 no.6
• /
• pp.87-96
• /
• 2005

In this paper, a selective visual attention module based on motion stimuli is introduced for the purpose of detecting ROI(region of interest) or FOA(focus of attention) in motion pictures. Analysis of motion fields in our approach is in direct contrast to some of the previous studies of selective visual attention module. Motion that presents temporal visual saliency in an aspect between two successive frames is analyzed based on psychological studies in 'DORF(double opponent receptive fields)' and 'NF(noise filtration)' in MT(middle temporal cortex). Analyzed results are integrated based on the theory of 'motion integration' in MT to obtain a single conspicuous region. Experiments through a human subjective evaluation showed generally accepted results.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.4
• /
• pp.874-880
• /
• 2007

Capillary Suction Time(CST) and Specific Resistance to Filtration(SRF) were commonly used to evaluate the sludge dewatering behaviors. A coupled equation was developed through the mathematical theory which represented both CST and SRF as the physical filterability of the ultrasonically treated sludge. The model for coupling CST and SRF includes both equipment variables and variables related to sludge characteristics, and verified with the results from experiments. The results of the theoretical and experimental study showed that a good correlation relationship among dewaterability indices.

• Journal of the Korean Geosynthetics Society
• /
• v.5 no.3
• /
• pp.31-36
• /
• 2006

In this study, stress relaxation behaviors of nonwoven geotextile and geomembrane which have protection, filtration and drainage, water barrier functions, respectively were examined. 'Theory of transition phenomen' was applied to interpretate the stress relaxation behaviors of two geosynthetics. The initial and later relaxation times for stress relaxation behaviors of geosynthetics were derived from the constitutive equations. The initial relaxation behaviors of these geosynthetics were dependent on the additional strains and were especially faster with temperature. Finally, both relaxation times of geosynthetics were shorter with additional strain and temperature and the reduction of relaxation times of nonwoven geotextile were larger than those of geomembrane.

• Journal of the Korean Geosynthetics Society
• /
• v.3 no.4
• /
• pp.21-27
• /
• 2004

Stress relaxation behaviors of nonwoven geotextile and geomembrane which have protection, filtration and drainage, water barrier functions, respectively were analyzed. 'Theory of transition phenomena' was applied to interpretate the stress relaxation behaviors of two geosynthetics. The initial and later relaxation times for stress relaxation behaviors of geosynthetics were derived from the constitutive equations. The initial relaxation behaviors of these geosynthetics were dependent on the additional strains and were especially faster with temperature. Finally, both relaxation times of geosynthetics were shorter with additional strain and temperature.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.381-384
• /
• 2009

강변여과는 인공함양을 활용한 대체수자원의 대표적 방법으로 하천수를 충적층으로 통과시켜 간접취수함으로써 오염저감과 수질사고 대처 능력의 장점을 가지고 있다. 유럽을 시작으로 많은 선진국에서는 150년 정도의 개발역사를 가지고 있으며, 우리나라에서도 현재 낙동강을 중심으로 강변여과를 활용한 상수도 공급이 이루어지고 있다. 본 논문은 이러한 강변여과 개발을 위한 개발전 개발전략과 적절한 개발위치 선정에 대한 연구로서 게임이론적 접근을 시도하였다. 강변여과 개발을 위한 지자체간 협력 게임이론을 적용함으로써 협력관계를 통한 추가이익 발생이 가능하게 되어 강변여과 개발타당성을 확보할 수 있다. 본 연구에서는 입지 선정에서 대상 후보지의 인자비교를 위한 일부 항목의 자료 유무에 상관없이, 적지분석이 가능한 게임모형을 개발하고 그 적용성에 대해 검토하였다.