• Korean Chemical Engineering Research
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• v.43 no.3
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• pp.366-370
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• 2005

Pervaporation process using a NaY zeolite membrane was applied for separation of water generated in an esterification process as a byproduct. From the binary mixture of water and either ethyl acetate or acetic acid and the ternary mixture of water, ethanol and ethyl acetate which might be present in an esterification reaction for manufacturing ethyl acetate, water was separated by the membrane pervaporation. It was investigated how the operating parameters such as an organic concentration and a temperature affected the permeate flux and the separation factor of water. For the feed mixture of water/ethyl acetate, the total flux and the separation factor of water were observed to be $930-5,000g/m^2/hr$ and 3,700-8,000, respectively. Also it was found for ternary mixtures of water/ethanol/ethyl acetate that the total flux was $1,300-3,900g/m^2/hr$ and the separation factor was 530-1,600. A pervaporation process might be applied in an esterification process since both the total flux and the separation factor of water through the NaY zeolite membrane were shown to be very high.

• Food Science of Animal Resources
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• v.34 no.5
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• pp.614-621
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• 2014

This study was conducted to isolate and characterize bacteriocin-producing bacteria against Clostridium perfringens (C. perfringens) from domestic animals to determine their usefulness as probiotics. Bacteriocin-producing bacteria were isolated from pig feces by the spot-on-lawn method. A total of 1,370 bacterial stains were isolated, and six were tentatively selected after identifying the inhibitory activity against the pathogenic indicator C. perfringens KCTC 3269 and KCTC 5100. The selected strains were identified as Enterococcus faecalis (E. faecalis) by 16s rRNA sequencing. Most of the isolated bacterial strains were resistant to 0.5% bile salts for 48 h and remained viable after 2 h at pH 3.0. Some E. faecalis also showed strong inhibitory activity against Listeria monocytogenes KCTC 3569, KCTC 3586 and KCTC 3710. In the present study, we finally selected E. faecalis AP 216 and AP 45 strain based on probiotic selection criteria such as antimicrobial activity against C. perfringens and tolerance to acid and bile salts. The bacteriocins of E. faecalis AP 216 and AP 45 strains were highly thermostable, showing anticlostridial activities even after incubation at $121^{\circ}C$ for 15 min. These bacteriocin-producing bacteria and/or bacteriocins could be used in feed manufacturing as probiotics as an alternative to antibiotics in the livestock industry.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.6
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• pp.548-555
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• 2014

As a considerable, experimental approach, an Auto-carriage type of $CO_2$ welding machine and a MIG(Metal Inert Gas) welding robot under inert gas atmosphere were utilized in order to realize Al 5083 welding applied to hull and relevant components of green Al leisure ships. This study aims at investigating the effect of welding conditions(current, voltage, welding speed, etc) on thermal deformation that occurs as welding operation and tensile characteristics after welding, by using Al 5083, non-ferrous material, applied to manufacturing of co-environmental Al leisure ships. With respect to welding condition to minimize the thermal deformation, 150A and 16V at the wire-feed rate of 6mm/sec were acquired in the process of welding Al 5083 through an auto carriage type of $CO_2$ welding feeder. As to tensile characteristics of Al 5083 welding through a MIG welding robot, most of tensile specimens showed the fracture behavior on HAZ(Heat Affected Zone) located at the area joined with weld metal, except for some cases. Especially, for the case of the Al specimen with 5mm thickness, 284.62MPa of tensile strength and 11.41% of elongation were obtained as an actual allowable tensile stress-strain value. Mostly, after acquiring the optimum welding condition, the relevant welding data and technical requirements might be provided for actual welding operation site and welding procedure specification(WPS).

• The Journal of Fisheries Business Administration
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• v.23 no.2
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• pp.101-128
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• 1992

How to distribute fisheries catches from producer to consumer is very important for everybody joined fisheries marketing channels (FMC), because most people are influenced their revenue and expenditure through marketing channels. Many institutions in Korea after 1960's have tried to develop the rationalization of FMC, but they have not gotten the satisfactory results in general in spite of a lot fruits. Comparing with general manufacturing industry, the fisheries industry has some specializations in the marketing channels. It makes them unique structure included wholesale market system similiar to fresh (perishable) food market with expertised technology. Wholesale market collects, distributes the fisheries catches and evaluates in by auction or bidding without consideration of producer's opinion. It is very necessary institution to make a decision to equatible price for fresh food and to play an important role for marketing effectiveness with minimum total transation and with massed reserve among institutions. But it has two weak points to increase the marketing cost and to make products bad fresh (perishable). Therefore, both Producer and consumer want to find the direct channels not to pass through wholesale market and to get more profit. I wanted to explain what problems of traditional FMC are and why the direct channel is necessary as follows in this paper. Chapter II : The types and specialization of FMC Chapter III : The structure and problem of fisheries wholesale market channel Chapter IV Marketing cost of FMC and direct channel I suggested when the direct channel in FMC is designed, new planner must carry out marketing functions which are performanced by wholesaler, middle man and the joined members of auction at wholesale market. In view of consumption area, these functions are : (1) the finding of production partner to make a business ; (2) communication of information ; (3) collecting ; (4) distribution ; (5) selecting and grading ; (6) evaluating ; (7) financing and payment ; (8) organization, in view of consumption area. The government must support also the group or individual of new direct channels to succeed it with (1) furnishing of market information (2) supplying of land and facility (3) financing (4) feed-back of dierct channels totally (5) making an opportunity of communication between producer and consumer. I want to emphasize again wholesale market is necessary and important institution for equatible price of fresh food in spite of the its weak points. At the same time. the direct channels are necessary to reduce the marketing cost and to keep better fresh food.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.10
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• pp.1377-1385
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• 2011

This study was conducted to determine the nutritive value of live yeast culture (RumiSacc, Saccharomyces cerevisiae) and to investigate its effects on milk yield, milk composition and some blood parameters in lactating cows. Six multiparous Holstein cows were allocated to two groups of three cows and assigned randomly to one of two diets in a cross-over experiment. Daily 50 g RumiSacc was top dressed at the p.m. feeding for the treatment group. RumiSacc supplied a high protein and energy with high organic matter digestibility values (83.35%) determined by in vitro enzymatic analysis. Yeast culture supplementation significantly increased milk yield, tended to increase fat yield, protein yield and lactose yield of milk. Methylated fatty acid level of 18:3 (n-3) in milk fat was increased by yeast culture supplementation. The concentrations of methionine, phenyalanine, tyrosine, tryptophan and taurine were significantly increased with dietary inclusion of yeast culture. Live yeast culture supplementation did not affect other performance characteristics, milk quality characteristics and blood parameters. As a conclusion live yeast culture (RumiSacc, Saccharomyces cerevisiae) had high nutritive value and positive effects on milk production and some milk quality characteristics in lactating cows under field conditions.

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.101-107
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• 2003

In this study, we provide a single element log-periodic antenna that the feeding networks and array structures are aperture coupled and series dipole array type. We made the antenna for direct receiving the Moogoongwha satellite broadcasting signal. The transmission power was able to feed the patch dipole in series due to lay perpendicularly 8 series patch dipole on tapered slot. The patch dipole radiation pattern which fed in series power, make the main beam direction up $37^{\circ}{\sim}42^{\circ}$ within the BS/CS bandwidth. The main beam gain was measured 9.31~11.03 dBi. Using 32 elements to array the elements properly, we acquire $4{\times}8$ array structure on limited PCB board. As a result, it has been found that the new planar DBS antenna structure have high gain over 10dBi and acceptable elevation angle over 42 degree, and we can apply this result to commercial DBS reception antenna manufacturing.

• Journal of the Korean Wood Science and Technology
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• v.29 no.2
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• pp.100-108
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• 2001

An understanding of potential lumber cutting yields may lead to increased utilization of the lower grades of lumber in wood industry. Computer simulations of rough-mill operations require a lumber database as input to give reasonable estimates of such yields. The lumber database must contain detailed information regarding the location and type of defects, and then all manufacturing sequences can be tested with the same raw material. However, no suitable lumber database with mapped defects exists for Korean wood industry. In this study lumber databases of Pinus densiflora S. et Z and Quercus acutissima which are the main Korean domestic species were developed to prepare for coming era of "utilization of domestic species" in the near future. These databases were put into lumber cut-up simulation model(gang-rip-first simulator) to investigate the part yields. Gang-rip first simulation showed average part yields of 44.75% and 63.10% for Quercus acutissima and Pinus densiflora lumber database developed, respectively. In most cases process set-up of fixed blade best feed showed the best part yields and the level of acceptable defects could not make significant differences in part yields.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1190-1199
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• 2014

As a considerable, experimental approach, an autocarriage type of $CO_2$ welding machine and a MIG(metal inert gas) welding robot in the inert gas atmosphere were utilized in order to realize Al 5083 welding to hull and relevant components of green leisure ships. This study aims at investigating the effect of welding conditions(current, voltage, welding speed, etc.) on thermal deformation that occurs as welding operation and tensile characteristics after welding, by using Al 5083, nonferrous material, applied to manufacturing of eco-environmental leisure ships. With respect to welding condition to minimize the thermal deformation, 150 A and 16 V at the wire-feed rate of 6 mm/sec were acquired in the process of welding Al 5083 through an auto carriage type of $CO_2$ welding feeder. As to tensile characteristics of Al 5083 welding through a MIG welding robot, most of tensile specimens showed the fracture behavior on HAZ(heat affected zone) located at the area joined with weld metal, except for some cases. Especially, for the case of the Al specimen with 5 mm thickness, 284.62 MPa of tensile strength and 11.41 % of elongation were obtained as an actual allowable tensile stress-strain value. Mostly, after acquiring the optimum welding condition, the relevant welding data and technical requirements might be provided for actual welding operation site and welding procedure specification (WPS).

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.6
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• pp.32-37
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• 2006

Micron size Co-alloy(T800) powder was coated on Inconel 718 by HVOF thermal spraying for the studies of the improvement of durability of high speed spindle by using Taguchi program for the parameters of spray distance, flow rates of hydrogen and oxygen and powder feed rate. The optimal coating process was determined by the studies of coating properties such as micro-structure, porosity, surface roughness and micro hardness. Friction and wear behaviors of coatings were investigated by sliding wear test at room temperature and $1000^{\circ}F(538^{\circ}C)$. At both room temperature and $538^{\circ}C$ the sliding wear debris and friction coefficients of the coating were drastically reduced compared with the surface of non-coated parent material. This shows that Co-alloy powder coating is highly recommendable for the durability improvement surface coating of high speed air-bearing spindle. At high temperature wear traces and friction coefficients of both coating and non-coating were drastically reduced compared with those of room temperature since the brittle oxides were formed easily on the surface, and the brittle oxide phases were attrited by the reciprocating sliding wear according to the complicated mixed wear mechanisms These oxide particles, partially melts and the melts play role as lubricant and reduce the wear and friction coefficient. This also shows that Co-alloy powder coating is highly recommendable far the durability improvement surface coating on the surface vulnerable to frictional heat such as high speed spindles.

• Membrane Journal
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• v.23 no.5
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• pp.384-391
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• 2013

We prepared composite membrane which was made with polysulfone supported hollow fiber membrane coated with Hyflon AD to eliminate $CO_2$ gas from mixed-gases which were generated in DME manufacturing processes. The performance of module about simulated flaring gas was measured by using manufactured composite membrane. 1-stage evaluation result shows $CO_2$ concentration was below 3% at 1.2 MPa and at Stage cut 0.24 above. In addition $CO_2$ removal rate and $CH_4$ recovery rate was 80% respectively at the same condition. 2-stage evaluation result shows, when the $CO_2$ concentration of product gas was fixed at 5%, recycled $CO_2$ at stage cut 0.074 had the same concentration as the feed gas and the recovery rate of $CH_4$ was 99% at the moment.