• Textile Coloration and Finishing
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• v.32 no.3
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• pp.176-183
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• 2020

In order to study wearable air cushion materials capable of responding to massive impact in high-altitude fall situation, high tenacity woven fabrics were bonded by heat only depending on various type of thermoplastic films and then mechanical properties were measured. Tensile strength, elongation, and 100% modulus measurement results for 4 types of films show that TPU-2 has higher impact resistance and easier expansion than PET-1. After thermal bonding, the combination with the highest tensile strength was a material with a TPU-2 film for nylon and a PET-2 film for PET, so there was a difference by type of fabric. The tear strength of the bonded materials were increased compared to the fabric alone, which shows that durability against damage such as tearing can be obtained through film adhesion. All of the peel strengths exceeded the values required by automobile airbags by about 5 times, and the TPU-2 bonded fabric showed the highest value. The air permeability was 0 L/dm2 /min. For both the film and the bonded material, which means tightness between the fabric and the film through thermal bonding. It is expected to be applied as a wearable air cushion material by achieving a level of mechanical properties similar to or superior to that of automobile airbags through the method of bonding film and fabric by thermal bonding.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.651-657
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• 2020

Fluidization processes in which solid particles vividly move like gas or liquid have been widely used in various industrial sectors, such as thermochemical energy conversion and polymerization processes for general purpose polymer resins. One of the general purpose polymer resins, LLDPE(Linear low-density polyethylene) resins have been produced in bubbling fluidized bed processes in the world. In a bubbling fluidization polymerization reactors, LLDPE particles with relatively larger particle size and low density are fluidized by hydrogen gas for polymerization reaction. Though LLDPE polymerization reactors are one of bubbling fluidization processes, slugs that have negative impact for reaction exist or occur in these processes. Therefore, the fluidization state of LLDPE particles was investigated in a simulation model similar to a pilot-scale polymerization reactor (0.38 m l.D., 4.4 m High). In particular, the effect of gas velocity (0.45-1.2 m/s), solid density (900-199 kg/㎥), solid sphericity (0.5-1.0), and average particle size (120-1230 ㎛), on bed height and fluidization state were measured by using a CPFD(Computational particle-fluid dynamics) method. With CPFD analysis, the occurrence of a flat slug was visualized. Also, the change in particle properties, such as particle density, sphericity, and size, could reduce the occurrence of slug and bed expansion.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.23 no.3
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• pp.151-162
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• 2017

The purpose of this study was to investigate the quality change of fresh-cut tumeric (Curcuma Longa Linne) according to packaging method during storage time. The fresh-cut tumeric were packaged in three different methods : degassing valve packaging (DVP), $CO_2$ gas absorber packaging (CAP) and micro-perforated packaging (MPP). After the samples were packaged, they were stored for 15 days at 4 and $23^{\circ}C$ respectively. The following parameters were observed to indicate the quality changes of the samples: weight loss, CIE $L^*a^*b^*$ colour difference, variation of gas composition inside the package, curcumin contents and changes in hardness of fresh-cut tumeric. DVP did not effectively release $CO_2$ gas to the outside. MPP was suitable to release $CO_2$ gas. However, MPP showed very fast browning and erosion, because a large amount of oxygen was introduced through the perforated hole on the film. CAP was most effective packaging method to inhibit browning, to prevent expansion of the packaging by $CO_2$ gas and to minimize weight loss of fresh-cut tumeric.

• Journal of Wetlands Research
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• v.19 no.1
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• pp.45-51
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• 2017

Nepal is a landlocked mountainous country in South Asia, located between China to the north and India to the south, east, and west. As such, wastewater management has become one of the most significant problems in urban area of Nepal. In Nepal, the centralized wastewater treatment systems were dysfunctional due to high cost of operation, discontinuous power supply, lack of proper maintenance and proper technical workforce to address the issues. As such, constructed wetlands (CW) were applied to treat various secondary wastewater as alternative to wastewater treatment facilities. Generally, efficiency and sustainability of CW technology depends on proper operation and maintenance and active community involvement. This study summarizes information about 26 CW in Nepal. Specifically, factors including data banking, removal efficiency, quality of discharged water, compliance to water quality standard of Nepal and operation and maintenance were investigated. Considering removal efficiency per pollutant, Ka-1 achieved the greatest reduction for most pollutant followed by B-1, L-3, Ka-5 and K-1. Nepal has practiced CW technology for more than 2 decades but currently, development of technology was interrupted by the inefficient performance of existing facilities. Public awareness about the technology, natural disaster, unavailability of specified substrate materials, lack of fund for further research and experiments has hindered the expansion of technology. In spite of these concerns, CW was still proven as an alternative solution to the present wastewater problems in urban areas of Nepal.

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.382-393
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• 2012

The purpose of this study was to research the vegetation structure of the Bongamsa Forest Genetic Resourses Resreve Area in Mt. Heuyang, Mungyeong, Gyeongsangbuk-do. For doing this, ninety-two plots($100m^2/plot$) were set up and investigated, and then Classification analysis and Ordination analysis were carried out. As a result, the vegetation of this area is divided to nine communities; Quercus mongolica community, Quercus variabilis community, Pinus densiflora community, Pinus densiflora-Quercus serrata community, Pinus densiflora-Quercus mongolica community, Quercus serrata community, Decideous broad leaf community, Pinus koraiensis community, Larix kaempferi community. To compare between the communities, statistical analyses were conducted with topographical condition and the results of the vegetational investigation of each community. In altitude, slope, the number of species, the number of individuals in canopy and the number of individuals of understory layer, the mean averages among the communities were different in statistically significance. Then we analysed the vegetation community structure with Importance Percentage of each stratum. The oak tree communities were expected to keep or expand the actual communities because oak trees are spread widely in canopy and understory layers. But the pine tree dominant communities were expected to be succeeded to oak tree communities in the future because of the wide expansion of oak trees.

• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.320-333
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• 2016

This study was carried out to elucidate the development of unprecedented water-bloom caused by a single species of colonial green algae Eudorina elegans in the upstream area of the Seungchon weir located in the Yeongsan River from late April to May 2013. The Yeongsan River is typically regulated system and the waterbody is seriously enriched by both external and internal sources of nutrients. Seasonal algal outbreaks were highly probable due to various potential factors, such as the excessive nutrients contained in treated wastewater, slow current, high irradiation and temperature, in diatom (winter), green algae (spring) and bluegreen algae (summer). Spring green-tide was attributed to E. elegans with level up to $1,000mg\;m^{-3}$(>$50{\times}10^4cells\;mL^{-1}$). The bloom was exploded in the initial period of the algal development and after then gradually diminished with transporting to the downstream by the intermittent rainfall, resulting in rapid expansion of the distribution range. Although the pulsed-flows by the weir manipulation was applied to control algal bloom, they were not the countermeasures to solve the underlying problem, but rather there still was a remaining problem related to the impact of pulsed-flows on the downstream. The green-tide of E. elegans in this particular region of the Yeongsan River revealed the blooming characteristics of a colonial motile microalga, and fate of vanishing away by the succeeding episodic events of mesoscale rainfall. We believe that the results of the present study contribute to limno-ecological understanding of the green-tide caused by blue-green algae in the four major rivers, Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.6
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• pp.827-834
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• 2018

Objective: The aim of this study was to compare the effects of $36.5^{\circ}C$ and $38.5^{\circ}C$ incubation temperatures on the maturation of bovine oocytes and developmental competence of embryos. Methods: In experiment 1, oocytes were maturated in bicarbonate-buffered TCM-199 for 22 hours in a humidified atmosphere of 5% $CO_2$ in the air at either $36.5^{\circ}C$ or $38.5^{\circ}C$ and nuclear maturation status were determined. In experiment 2, in vitro fertilized oocytes were allocated randomly into synthetic oviductal fluid medium with or without a mixture of 1 mM L-glutathione reduced and 1,500 IU superoxide dismutase and cultured in a humidified atmosphere of 5% $CO_2$, 5% $O_2$, and 90% $N_2$ in the air at $38.5^{\circ}C$ for 8 days. Results: There were no significant differences between incubation temperatures in terms of oocyte maturation parameters such as cumulus expansion, first polar body extrusion and nuclear maturation. Incubation temperatures during in vitro maturation had no effects on developmental competence of embryos, but supplementation of antioxidants increased (p<0.05) developmental competence of the embryos. Blastocysts from oocytes matured at $38.5^{\circ}C$ had comparatively higher inner cell mass, but low overall and trophectoderm cell numbers (p<0.05). Conclusion: The results of present study showed that maturation of bovine oocytes at $36.5^{\circ}C$ may provide a suitable thermal environment for nuclear maturation and subsequent embryo development.

• Korean Journal of Materials Research
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• v.4 no.6
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• pp.611-619
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• 1994

The formation of , $\beta$-quartz solid solution in the $LiO_2-Al_2O_3-SiO_2$glasses containing $TiO_{2}$ and $ZrO_{2}$ as nucleating agents was investigated for various temperatures and times. Linear thermal expansion coefficients of base glasses and crystallized glasses were $45\sim 55 \times 10^{-7} \textrm{cm}/^{\circ}C$ and $ -8\sim +8 \times 10^{-7}\textrm{cm}/^{\circ}C$ ($25^{\circ}C \sim 525^{\circ}C$), respectively. The crystal phase formed by heat-treatment below $900^{\circ}C$was , $\beta$--quartz solid solution, and the crystal sizes were less than 0.21m. On the other hand, the crystal size of the base glasses containing 3.5 wt% MgO is relatively uniform and is independent with temperature. The specimen containing 3.5 wt% ZnO shows a minimum crystal size(O.l8$\mu \textrm{m}$), and it strongly depends on temperature of heat-treatment.

• Korean journal of food and cookery science
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• v.24 no.6
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• pp.837-848
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• 2008

The objectives of this study were to investigate the quality of ginseng makgeolli during the fermentation and aging period, and to develop Jeungpyun manufactured by ginseng makgeolli. Four different amounts of ginseng powder (0, 2, 4 and 6 g) were added to the filtered mash which was fermented for 4 days at $24^{\circ}C$ and then aged for 6 days at $4^{\circ}C$ The quality of Jeungpyun batter containing 0, 2, 4 and 6% ginseng during fermentation, and the sensory, color and textural characteristics of ginseng Jeungpyun were analyzed. The pH of jeungpyun batter without ginseng was lower than the other batters. During 4 hours of fermentation of the batter at $30^{\circ}C$, the pH of the batter significantly decreased. The expansion volume of the batter without ginseng increased 4.11 times after 4 hours of fermentation, whereas batters with 2, 4, and 6% ginseng increased 1.70 times. The L value of Jeungpyun decreased by increasing the concentration of ginseng However the a and b values of Jeungpyun significantly increased with an increase in the concentration of ginseng. The results of the sensory evaluation showed that Jeungpyun with 2% ginseng had the highest flavor, taste and overall acceptability scores. In the textural analysis, the hardness of Jeungpyun increased by increasing the concentration of ginseng after 6 days of storage at $20^{\circ}C$. This study showed that Jeunpyun containing 2% ginseng was the optimum addition level.

• Journal of the Korea Society of Computer and Information
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• v.16 no.10
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• pp.111-120
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• 2011

The purpose of this study is to analyze the results of training programs for strengthening teachers' ICT competency and to suggest the ways to improve the existing ones. To do this, we conducted literature review, web survey with teachers, and in-depth interview with training program operators. The results of the online survey indicated that generally speaking, the programs had been operated desirably, although three programs(Thinking with Technology Course, Essential Course, e-PBL Instructional Design Course) needed to take additional efforts for their effectiveness and efficiency. According to the results of in-depth interview with training operators, they demanded re-training for lecturers, self career development, quality control of regional delivery training, expansion of training periods, and post-supports after training etc.