• Journal of Biosystems Engineering
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• 제26권4호
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• pp.371-378
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• 2001

This research devoted to develop an incubator that could make an optimum environment condition according to days of age for suckling pigs to decrease the mortality and improve the rate of the weight gain of the suckling pigs. Results obtained from this research summarized as follows: 1. Several experiments were carried out at the farm to find the effect of incubator developed for suckling pigs on weight gain by season. The total average gain of the weight of the treatment group was around 6∼22kg, and 6∼23kg higher than control group at the first experiment (April 19), at the second (July 30), and at the third (September 23), year of 2000 experiment, respectively. There were no significant differences ($\alpha$=5%) of the total weight gain among treatment groups. There was, however, a significant difference ($\alpha$=5%) of the total weight gain between the control and treatment groups and it was considered to be that the incubator had efficiency for weight gain of the suckling pigs. 2. The survival rate of the control group was 87% in the total sample number of 92, meanwhile, which of the experiment group was 98% in the total sample number of 50 suckling pigs. 3. Finally, economic analysis was executed for suckling pigs based on a farm size of breeding 500 sows. The results showed that a break-even point was around 9 months and the annual profit of ￦52,265,694 was expected after the break-even point.

• 한국가축번식학회지
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• 제7권1호
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• pp.41-51
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• 1983

The purpose of this experiment was to investigate the effects of adrenalectomy and PMSG treatment on reproductive organs and serum steroid hormone level in immature female rats. The animals used in this experiment were 25 days old female rats weighing a, pp.oximately 70g. They were randomly divided into two groups of intact rat group (Int-) and adrenalectomized rat group (Adx-) and each group were subdivided into two groups of Non-PMSG (-Cont) and PMSG treated (-PMSG) group. The rat of PMSG-treated group (-PMSG) was administered subcutaneously with 25 IU PMSG on first day (9 a.m.) after adrenalectomy. The adrenalectomized rat groups were su, pp.ied with saline solution through the experiment period. The rate of ovulation and vaginal opening and reproductive organ weights were observed at 8, 32, 56, 80 and 104 hours after PMSG treatment. At the same time, the serum level of estradiol-17${\beta}$ and progesterone were measured by the radioimmunoassay. The results obtained were as follows: 1. Ovulation was shown at 56 hours after treatment in Int-PMSG group and Adx-PMSG group and Adx-PMSG group. The rate of ovulation was very low in PMSG-treated groups, but it was increased in 80 to 90% at 104 hours after treatment. However, there was no ovulation in Int-Cont group and Adx-Cont group. 2. Vaginal opening was shown at 56 hours after treatment in Int-PMSG group and Adx-PMSG group and a, pp.ared in 80% at 104 hours after treatment. The rate of vaginal opening in PMSG-treated groups was very low, but Int-Cont group and Adx-Cont group had no vaginal opening. 3. The weight of ovary and uterus in two PMSG-treated groups were increased with the elapse of time after treatment and were significantly heavy in all observation time, but changes in Int-Cont group and Adx-Cont group were not recognized. The weights of ovaries and utera in Adx-Cont group were increased with the elapse of time. 4. The level of serum estradiol-17${\beta}$ was remarkably increased in PMSG-treated groups (Int-PMSG and Adx-PMSG groups) compared with Int-Cont and Adx-Cont group, and significant difference was recognized between Non-PMSG group and PMSG-treated group in the experimental period. Especially, the highest levels of Int-PMSG groups and Adx-PMSG groups were shown at 80 and 56 hours after treatment and after ward estradiol-17${\beta}$ levels of PMSG-treated groups were decreased. However, changes of the levels did not a, pp.ared in Non-PMSG groups at 104 hours after treatment. 5. The level of serum progesterone in PMSG-treated groups was significantly increased between 80 and 104 hours after treatment. With the elapse of time, the level was increased in all observed groups except for Int-Cont and Adx-Conx group. And the order from the highest level at 104 hours after treatment was Int-PMSG, Adx-PMSG, Int-Cont and Adx-Cont group.

• 환경위생공학
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• 제11권1호
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• pp.45-55
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• 1996

An experimental research was conducted in order to study the combined treatment o of municipal landfill leachate and municipal sewage. The landfill leachate was that of Nanjido landfill site, and the municipal sewage was that of Chungnang municipal sewage treatment plant in Seoul. Several sets of bench~scale sequencing batch reactor(SBR) were used as e experimental apparatus. Specially investigated items in this experiment were the removal efficiency of substrate and the influence of treatment time. The experiment lasted for about 2 years. The result are as follows ; 1. The characteristics of leachate were pH 7.5~8.2, BOD 80~336mg/L, COD 908~1,460mg/L, NH3-N 1,409~2,330mg/L, T~P 2.7~7.lmg/L, Cl~3,540~4,085mg/L, a and heavy metals are a very small amount. And the characteristics of sewage were pH 6.9~7.3, BOD 78.4~129.3mg/L, COD 121.2~305.0mg/L, T~N 14.9~36.4mg/L, T-P 2.3~8.9mg/L. 2. The treatability of leachate alone was not treat well. So for the good treatment of leachate, it was necessary to deal with the pretreatment before bi이ogical treatment and a combined treatment of municipal sewage. 3. The various contents of the leachate were 5%, 10%, 30%, and 50%, and the removal efficiency of COD was 86.0%, 82.8%, 60.6%, and 31.7%. The maximum content of the leachate which could be sucessfully treated by SBR in the combined treatment was 10% of that of sewage. And the removal efficiency of COD increased n notably, as its treatment time increased. 4. The various contents of the electrolytic treated leachate were 5%, 10%, 30%, and 50%, and the removal efficiency of COD was 89.9%, 86.1%, 79.2%, and 69.8%. The maximum content of the leachate which could be sucessfully treated by SBR in the combined treatment was 30 % of that of sewage. And the removal efficiency of C COD increased notably, as its treatment time increased.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1998년도 춘계 학술대회지
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• pp.99-100
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• 1998

• 한국표면공학회지
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• 제51권2호
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• pp.87-94
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• 2018

Various sealing techniques were applied to the anodized 5083 aluminum alloy for marine environment to reduce corrosion and cavitation erosion damage. Electrochemical experiments and cavitation erosion tests were conducted to evaluate the corrosion resistance and cavitation resistance of the anodic oxide film treated with sealing in natural seawater solution. Then, damaged surface morphology was analyzed by scanning electron microscope(SEM) and 3D microscope. As the results of the electrochemical experiments, it was observed that the surface damage of all the experimental conditions in the anodic polarization experiment was locally grown by the combination of crack and corrosion damage. In the Tafel analysis, the corrosion resistance of all sealing treatment conditions was improved compared to the anodizing. On the other hand, cavitation erosion tests showed that the anodizing and all the sealing treatment conditions generated local pit damage by cavitation erosion attack and grew to crater damage in the observation of damaged surface by SEM. Also, the weight loss and the surface damage depth measured with the experiment time presented that most of the sealing treatment conditions showed better cavitation erosion resistance than the anodizing, and they had an incubation period at the beginning of the experiment.

• 한국수정란이식학회지
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• 제28권1호
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• pp.41-48
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• 2013

This study examined the motility of either the unattached(upper) or attached(lower) Hanwoo sperm to bovine oviduct epithelial cell(BOEC) monolayers to determine whether there are any changes in their motility during co-culture. The cleavage and blastocyst development rate were compared among different preincubation methods in-vitro, after oocytes were fertilized in-vitro with Hanwoo sperm on BOEC monolayers. The motility of frozen-thawed sperm in BOEC co-culture group was significantly higher than controls, especially at 5 hours and 6 hours (p<0.05) of incubation, in sperm treatment medium without heparin and caffeine. The motility of frozen-thawed sperm in BOEC co-culture group was significantly higher than controls, especially at 3 hours (p<0.05) and 6 hours (p<0.01), in sperm treatment medium containing heparin and caffeine. The motility of the attached( lower) sperm was significantly higher than the unattached(upper) sperm during co-culture with BOEC at all times(p<0.01 or p<0.05), except for 6 hours. After Hanwoo oocytes were fertilized in-vitro with the sperm that had been co-cultured with BOEC in sperm treatment medium containing heparin and caffeine, we determined the cleavage and blastocyst development rate, according to the preincubation methods. Both the cleavage and blastocyst development rate from 2 hour preincubation group were the highest, but significant difference was not recognized. These results show that BOEC plays an important role on sperm hyperactivation related to capacitation regardless of heparin and caffeine in sperm treatment medium. However, oviduct epithelial cell had no significant effect on the development of embryos after in-vitro fertilization in the presence of added heparin and caffeine in sperm treatment medium.

• 한국농공학회지
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• 제40권3호
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• pp.83-92
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• 1998

Field experiment was performed from August 1996 to January 1998 to examine the applicability of constructed wetland system for wastewater treatment in rural area. The pilot plant was installed in Kon-Kuk University and the school building septic tank effluent was used as an influent to the treatment basin. Hydraulic loading rate was about 0.1 6$0.16^3/m^2$ day and theoretical detention time in the system was 1.38 days. The treatment basin was composed of sand and reed. The influent DO concentration was low and many cases close to zero, but effluent concentration was higher than the influent which implies that oxygen was supplied naturally. The average concentration of influent BOD was 126mg/L, and with average removal rate of 69 % the average effluent concentration was 4Omg/L which satisfied the effluent water quality standard for the system of interest. The average influent concentration of COD was 2Olmg/L and average effluent concentration was 75mg/L with average removal rate of 60%. The performance of BOD and COD tends to deteriorate in the low temperature, and appropriate action needs to be taken during the cold winter time for stable operation. The average influent concentration of SS was 5Omg/L, and effluent was 1 1mg/L with average removal rate of 76% which satisfied the effluent water quality standard for the system of interest. The results for the regulated components, SOD and SS, from the experiment showed that constructed wetland system can meet the effluent water quality standards. The average influent concentration of total phosphorus was 25.6mg/L and average effluent concentration was 7.8mg/L with average removal rate of 63%. Not like the performance of the above components, average nitrogen removal rate was only 11.2% which is not satisfactory. Although, nitrogen is not regulated at this moment, it can cause many environmental problems including eutrophication. Therefore, nitrogen removal efficiency should be improved for actual application. From the result of the field experiment, constructed wetland system was thought to be an appropriate alternative for wastewater treatment in rural area.

• 펄프종이기술
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• 제30권4호
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• pp.59-68
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• 1998

This study was to investigate the effect of chitosan molecular weight, its charge density, and its surface coating treatment on the antibacterial properties of paper. For this study, E.coil was used for antibacterial experiment. Results obtained were as follows : 1. The antibacterial properties of chitosan was significant on the surface-treated sheet. 2. Antibacterial property surface treatment was appeared to be effective when film was formed on the paper surface. 3. The antibacterial properties of chitosan-treated paper was dependent on the amount and the molecular weight of chitosan used. The lower the molecular weight of the chitosan down to 30,000 the better the antibacterial properties in this experiment. 4. Determination of the degree of chitosan-deacetylation by colloidal titration method was consistent with the more complicated and conventional FT-IR method.

• Environmental Engineering Research
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• 제18권3호
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• pp.157-161
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• 2013

Treatment of textile wastewater by the electrocoagulation (EC) process is being investigated by this experimental study. The objective of this experiment is to observe the efficiency of the EC process in removing chemical oxygen demand (COD) and turbidity. In this experiment an iron electrode is used in the EC process, and different working parameters such as pH, current density and operating time were studied in an attempt to achieve a higher removal capacity. The results show that the maximum COD removal occurred at neutral pH at operating time 30 min. COD and turbidity removal reaches at maximum, with optimum consumption of electrodes, between current density 85-95 $A/m^2$, and only trace amounts of metals were determined in the EC treated effluent.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.265-266
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• 2006

The chemical conversion coating formed on magnesium alloy investigated for low cost and harmless in environment by using the colloidal silica as the main component. The film formed in 298 K is thick, the film, which was thought combination of Si-O, was formed. The film formed in 313 K is thinner than that in 298 K. The quantity of film formed at high temperature such as 333 K and 353 K is smaller than dissolved quantity. At the anodic polarization experiment, corrosion resistance in sealing by hot water after chemical conversion treatment in basic solution condition get worse than that in comparison with basic solution condition. In salt spray test, the ratio of black rust on specimen that did not conducted chemical conversion treatment was five times or more compared with those of chemical conversion treated specimen. The film thickness of chemical conversion coating produced by alkali treatment process is thinner than in comparison with that of specimen produced in basic chemical conversion treatment solution condition. It is thought, however, that it showed good corrosion resistance during salt spray test because the area of microcracks is small.