• Membrane Journal
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• v.7 no.2
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• pp.57-64
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• 1997

Membrane Distillation(MD) is reviewed as an application to new separation technology. Hydrophobic membrane which has been used to microfiltration is feasible material for MD process. MD has perfect selectivity under moderate temperature and is promised to simplify typical water treatment process. The principle of MD separation is phase transition by vapor-liquid interface at the pore of membrane surface. Feed and permeate temperature, composition, membrane wetting, heat and mass transfer phenomena affect the selectivity and flux of MD.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.4
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• pp.106-117
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• 2016

Recently, solar power plants have spread widely as part of the transition to greater environmental protection and renewable energy. Therefore, regular solar plant inspection is necessary to efficiently manage solar-light modules. This study implemented a test that can detect solar-light module faults using an UAV based thermal infrared camera and GIS spatial analysis. First, images were taken using fixed UAV and an RGB camera, then orthomosaic images were created using Pix4D SW. We constructed solar-light module layers from the orthomosaic images and inputted the module layer code. Rubber covers were installed in the solar-light module to detect solar-light module faults. The mean temperature of each solar-light module can be calculated using the Zonalmean function based on temperature information from the UAV thermal camera and solar-light module layer. Finally, locations of solar-light modules of more than $37^{\circ}C$ and those with rubber covers can be extracted automatically using GIS spatial analysis and analyzed specifically using the solar-light module's identifying code.

• Composites Research
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• v.36 no.4
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• pp.246-252
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• 2023

A secondary barrier made of glass fiber reinforced composites has been installed infinitely using automatic bonding machine(ABM) in membrane type LNG cargo containment system (CCS). At the same time, significant thermal stress due to cryogenic heat shrinkage has occurred in the composite on the non-bonding area between the adhesive fixation at both ends. There have been studies from the perspective of structural safety evaluation taking this into account, but none that have analyzed mechanical property taking an prolonged length into account. In this study, 2-parameter Weibull distribution statistical analysis was used to standardize reliable mechanical property for actual length, taking into account the composite's brittle fracture of ceramic material with wide fracture strength dispersion. Related experimental data were obtained by performing uniaxial tensile tests at specific temperatures below cryogenic condition considering LNG environment. As a result, the mechanical strength increased about 1.5 times compared to -20℃ at -70℃ and initial non-linear behavior of fiber stretched was suppressed. As the temperature decreased until the cryogenic, the mechanical strength continued to increase due to cold brittleness. The suggested mechanical property in this study would be employed to secure reliable analysis support material property when assessing the safety of secondary barrier's structures.

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.277-281
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• 2004

This study was performed to investigate the antimicrobial effect of the Fraxinus rhynchophylla extracts against food-borne pathogens. First, the Fraxinus rhynchophylla was extracted with methanol at room temperatures, and fractionation of the methanol extracts from Fraxinus rhynchophylla was carried out by using petroleum ether, chloroform, and ethyl acetate, and methanol respectively. The antimicrobial activity of the Fraxinus rhynchophylla extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The ethyl acetate extracts of Fraxinus rhynchophylla showed the highest antimicrobial activity against Staphylococcus aureus and Shigella dysenteriae. The synergistic effect has been found in combined extracts of Fraxinus rhynchophylla and Portulaca aleracea as compared to each extracts alone. Finally, the growth inhibition curve was determined using ethyl acetate extracts of Fraxinus rhynchophylla against Staphylococcus aureus and Shigella dysenteriae. The ethyl acetate extract of Fraxinus rhynchophylla showed strong antimicrobial activity against Staphylococcus aureus at the concentration of 4,000 ppm. The 4,000 ppm of ethyl acetate extract from Fraxinus rhynchophylla retarded the growth of S. aureus more than 24 hours and Shigella dysenteriae up to 36 hours. The ethyl acetate extracts of Fraxinus rhynchophylla has been shown the antimicrobial effect against Staphylococcus aureus and Shigella dysenteriae.

• Journal of the Korean Institute of Gas
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• v.3 no.3 s.8
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• pp.58-64
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• 1999

This paper has been analyzed for the stress behavior problems of the ring knot membrane unit using the finite element method about the pitch design of the membrane unit, which is one of the most important parameters in manufacturing of the membrane type LNG storage tanks. The FEM results have been compared those of the existing pitch design length. The safety problem of the ring knot membrane model, which is considered in this study, does not come out any more no matter what the pitch length is used in the extra large LNG storage tanks. But in the case of the membrane for LNG tankers, it is advantageous to design the pitch short because of fatigue strength caused by repeated loadings. Looking at the deformation behaviors of the membrane corrugation, the deformation of the hight in the y direction occurs $15{\~}50\%$ more than that of the width in the z direction. It shows also that the deformation of the membrane with $-162^{\circ}C$ cryogenic temperature is not so great compared with the deformation by hydrostatic pressure.

• Membrane Journal
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• v.6 no.1
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• pp.44-52
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• 1996

For the purpose of the optimal design of a frame and plate type of pervaporation module, model equations which can predict the effects of feed flow condition on the temperature distribution of the feed developed in the module were established and the temperature distribution with feed flow condition was investigated through the model si$$\mu$ation. With increasing the Reynolds number of feed flow in the module, the flow velocity gradient in the channel height-direction as well as the volume rate of feed which acts as energy source for the evaporation of perrneants on the permeate-side surface of a membrane increased to such an extent that both mass and heat flux in the channel height direction could increase and the temperature drop of feed due to the evaporation of the permeant could be reduced correspondingly. A decrease in channel height caused the temperature drop of feed because of decreasing feed flow in the module. It was observed that the si$$\mu$ation result on the effect of Re on the temperature distribution of feed in the module has an agreement with experiment.

• Membrane Journal
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• v.28 no.2
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• pp.136-141
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• 2018

Carbon dioxide ($CO_2$) exists not only as a component of natural gas, biogas, and landfill gas, but also as a major combustion product of fossil fuels which leads to a major contributor to greenhouse gases. Hence it is essential to reduce or eliminate carbon dioxide ($CO_2$) in order to obtain high fuel efficiency of internal combustion engine, to prevent corrosion of gas transportation system, and to cope with climate change preemptively. In recent years, there has been a growing interest in not only conventional membrane-based separation but also new adsorbent-based separation technology. Particularly, in the case of metal-organic frameworks (MOFs), it has been received tremendous attentions due to its unique properties (eg : flexibility, gate effect or strong binding site such as open metal sites) which are different from those of typical porous adsorbents. Therefore, in this study, stereotype of two MOFs have been selected as its flexible MOFs (MIL-53) representative and numerous open metal sites MOFs (MOF-74) representative, and compared each other for $CO_2/CH_4$ separation performance. Furthermore, varying and changeable separation performance conditions depending on the temperature, pressure or samples' unique properties are discussed.

• Membrane Journal
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• v.23 no.5
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• pp.360-366
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• 2013

The Poly (vinylidene fluoride) and poly (acrylonitrile) (PAN) hollow fiber composite membranes coated with poly (vinyl alcohol) (PVA) and poly (acrylic acid) (PAA) as the crosslinkig agent are prepared. The resulting membranes were characterized for aqueous 90 wt% ethanol solution by pervaporation techniques in terms of the permeability and separation factor. In general, as both the crsslinking reaction temperature and the crosslinking agent concentration increase, the permeability decrease while the separation factor tends to increase. And also the permeability increased and the separation factor decreased as the feed temperature increased. Typically, the permeability $502g/m^2hr$ at the feed temperature $70^{\circ}C$ was obtained for PVDF hollow fiber membrane prepared with the crosslinking agent PAA 3 wt% at the reaction temperature $60^{\circ}C$ whereas the separation factor 218 was shown for the membrane reacted with PAA 11 wt% and at $100^{\circ}C$ for the feed temperature $50^{\circ}C$.

• Journal of Animal Science and Technology
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• v.44 no.4
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• pp.453-458
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• 2002

In order to search for reliable rapid methods of estimating bacterial counts in pork, this study was tried to measure resazurin reduction time which is simple in experimental method, low in analytical cost, able to estimate bacterial count within short time. The results were summarized as follows; Correlation coefficient between initial bacterial log count(25$^{\circ}C$/72hr, Y) and resazurin reduction time(X) from blue color to pink color during incubation at 25$^{\circ}C$ and 30$^{\circ}C$ was higher than other conditions as -0.95 and -0.94, respectively. Considering correlation coefficient and reduction time, incubation temperature was compatible at 30$^{\circ}C$, and regression equation(RE) was Y = -0.4386X + 7.7870. At a bacterial load of $10^2$cfu/$cm^2$, $10^3$cfu/$cm^2$ and $10^4$cfu/$cm^2$ in pork, reduction time was 13.2hr, 10.9hr and 8.6hr, respectively. Correlation coefficient between initial bacterial log count(30$^{\circ}C$/72hr, Y) and resazurin reduction time(X) from blue color to pink color during incubation at 30$^{\circ}C$ was highest among other conditions as -0.93, and RE was Y = -0.4171X + 7.5540. At a bacterial load of $10^2$cfu/$cm^2$, $10^3cfu/$cm^2$ and $10^4cfu/$cm^2$ in pork, reduction time was 13.3hr, 10.9hr and 8.5hr, respectively. Correlation coefficient between initial bacterial log count(35$^{\circ}C$/72hr, Y) and resazurin reduction time(X) from blue color to pink color during incubation at 30$^{\circ}C$ was highest among other conditions as -0.93, and RE was Y = -0.3514X + 6.7513. At a bacterial load of $10^2$cfu/$cm^2$, $10^3$cfu/$cm^2$ and $10^4$cfu/$cm^2$ in pork, reduction time was 13.5hr, 10.7hr and 7.8hr, respectively.

• Journal of Animal Science and Technology
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• v.44 no.4
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• pp.459-474
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• 2002

The purpose of this study was to establish the optimal operation condition of the natural evaporation system(NES) which was used for reducing swine slurry. Especially the main point of this study is to estimate the effect of climate condition(clear & rainy) and spray type(batch & flow) for the evaporation rate of swine slurry applying the NES in summer. Experiment was performed from June to August, which was generally regarded as summer in Korea, with the spray type of batch in 2000 and that of flow in 2001. As a result of experiment for batch and flow type, the averaged evaporation rate was measured into 2.71 and 3.59 l/ton . $m^2$ . day on clear days and 0.62 and 0.66 l/ton . $m^2$ . day on raint days, respectively. Based on the calculated evaporation rate by the climate condition and the spray type, it was proved that the averaged reduction rate for total input(1t/day) were 15.99% and 3.19% on clear and rainy days and the evaporation rate of the flow type was superior to that of the batch type by 5%, approximately. Therefore, it was concluded that the supplementary equipment, such as fan, should by operated in rainy days and the spray type of flow rather than that of batch should be recommended to increase the evaporation rate in the natural evaporation system(NES).