• Journal of Korean Society of Environmental Engineers
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• v.28 no.6
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• pp.596-602
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• 2006

The effects of resin additives and inorganic compounds addition on the thermal decomposition of low density polyethylene(LDPE) resin have been studied in a thermal analyzer(TGA, DSC) and a small batch reactor. The silica-alumina type compounds tested were kaolinite, bentonite, perlite, diatomaceous earth, activated clay and clay. The resin additives were antiforgging-agent and longevity-agent. As the results of TGA experiments, addition of antifogging-agent, longevity-agent and clay increased the temperature of the maximum reaction rate($T_{max}$). The silica-alumina type inorganic materials increased the pyrolysis reraction rate in the order of activated clay, diatomaceous earth, bentonite, perlites, and kaolinite. In the DSC experiments, addition of antifogging-agent and clay decreased the heat of fusion and the heat of pyrolysis reaction. Bentonite decreased 20% of the heat of fusion and 25% of the heat of pyrolysis reaction. In the batch system experiments, the mixing of clay retarded the initial producing rate of fuel oil, but increased the yield of fuel oil. Addition of bentonite increased the yield of fuel oil from LDPE resin. Mixing of antifogging-agent and longevity-agent produced the fuel oil having lower carbon number. The amounts of the carbon number below 12 in fuel oil decreased with adding the clay. That below 23 in fuel oil increased with mixing of bentonite, perlite, kaolinite, and activated clay. But the mixing of diatomaceous earth did not affect the carbon contents of fuel oil from pure LDPE resin. In the silica-alumina type inorganic material used in this experiments, bentonite was the most effective from the pyrolysis heat, yields, and the characteristics of fuel oil.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.219-226
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• 1985

To investigate potential application of radurization technique as an effective tool for controlling histamine accumulation, histamine contents were determined in fresh Korean mackerel meat samples irradiated at six dose levels of gamma radiation up to 1 Mrad during 35 day-storage at $0^{\circ},\;5^{\circ}\;and\;10^{\circ}C$. Total bacterial counts, total volatile bases and trimethylamine contents were also estimated. The minimum and maximum doses for Korean mackerel were determined to be 0.2 and 0.5 Mrad, respectively. Irradiation induced redening of fish muscle tissue and redening appeared to be dose dependent. At low doses, this redening contributed positively to the overall sensory qualities. At 0.5 and 1.0 Mrad, on the other hand, meat samples were excessively redened to the extent that red and white muscle layers were not readily distinguishable. No appreciable histamine accumulation occured during entire 35 day-storage in fresh mackerel meats, whether irradiated or not, when they were kept at ice temperature. At $5^{\circ}C$, histamine started to accumulate slightly during late storage in the samples irradiated at low doses. Even in the unirradiated samples, the histamine accumulation did not exceed the level of 10.0 mg per 100g meat until the 28th day at $5^{\circ}C$. At $10^{\circ}C$, however, histamine accumulation in the unirradiated was phenomenal from very early storage and the values reached 827.5 mg per 100g meat by the 35th day, while histamine accumulation in the irradiated was severely suppressed. Irradiation invariably brought about a significant reduction of initial microflora, disrupting normal spoilage pattern. This was reflected in the suppression of not only histamine but also total volatile bases and trimethylamine accumulation during post-irradiation storage at refrigerated temperatures.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.783-791
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• 2015

A fluidized-bed reactor with an inside diameter of 0.1 m and a height of 1.2 m was used to study the effect of steam and catalyst additions to air-blown biomass gasification on the production of producer gas. The equipment consisted of a fluidized bed reactor, a fuel supply system, a cyclone, a condenser, two receivers, steam generator and gas analyzer. Silica sand with a mean particle diameter of $380{\mu}m$ was used as a bed material and calcined dolomite ($356{\mu}m$), which is effective in tar reduction and producer gas purification, was used as the catalyst. Both of Korea wood pellet (KWP) and a pellet form of EFB (empty fruit bunch) which is the byproduct of Southeast Asia palm oil extraction were examined as biomass feeds. In all the experiments, the feeding rates were 50 g/min for EFB and 38 g/min for KWP, respectively at the reaction temperature of $800^{\circ}C$ and an ER (equivalence ratio) of 0.25. The mixing ratio (0~100 wt%) of catalyst was applied to the bed material. Air or an air-steam mixture was used as the injection gas. The SBR (steam to biomass ratio) was 0.3. The composition, tar content, and lower heating value of the generated producer gas were measured. The addition of calcined dolomite decreased tar content in the producer gas with maximum reduction of 67.3 wt%. The addition of calcined dolomite in the air gasification reduced lower heating value of the producer gas. However The addition of calcined dolomite in the air-steam gasification slightly increased its lower heating value.

• Journal of Life Science
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• v.27 no.7
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• pp.754-759
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• 2017

The 100 l culture system was made on the basis of LED light, and Nannochloropsis oculata was cultured in f/2 medium at light intensity ($100{\mu}mol/m^2/s$), culture temperature ($20^{\circ}C{\pm}1^{\circ}C$) and LD cycle (12hr). As a result, the maximum biomass of 1.07 g/l was cultured as a result of 100 l mass culture at $100{\mu}mol/m^2/s$ and 24 mg/l nitrate concentration in LED blue (475 nm). The extraction was carried out using sonicator, homogenizer and chemical method 0.5M HCl shredding method. The contents of chlorophyll a, chlorophyll b and carotenoid were 1.6, 0.5 and 0.3 mg/g cell. When using homogenizer, it was measured at 1.0, 0.6 and 0.2 mg/g cell. The chemical breakdown method of 0.5M HCl, chlorophyll a, b, and carotenoid contents were measured as 0.9, 0.8, 0 mg/g cell. The highest amount of biomass during the distruption time was measured at 3.6 mg/g cell at 15 min disintegration and acetone, 3.6 mg/g cell of acetone, methanol, and ethanol were measured as effective solvents. Concentration was measured by using microfilter, disk type continuous centrifuge and tubular type continuous centrifuge were 16.0, 1.1 and 0.5 g/l, respectively. Four kinds of equipment such as hot air dryer, vacuum dryer, spray dryer and freeze dryer were tested to optimize the drying process. As a result, the recovery rates of spray dryer and freeze dryer were 80% and 60%.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.2
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• pp.83-99
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• 2005

To evaluate environmental charateristics of the South Sea and East China Sea on summer, water and sediment quality were measured in June 2001-2003. Surface layer was affceted by Warm water originated from the high temperature and salinity-Tsushima Warm Current, on the other hand, Yellow Sea Cold Water was spread to the bottom layer in the south-western part of the Jeju island, and salinity at stations near the Yangtze River was decreased below 29psu because of a enormous freshwater discharges. Thermocline-depth was formed at about 10m, and chlorophyll maximum layer was existed in and below the thermocline. COD(Chemical Oxygen Demand), TN(Total Nitrogen), and TP(Total Phosphorus) concentrations showed seawater quality grade II in surface layer of the most area, but concentrations of such as COD, Chl. a, TSS(Total Suspended Solid), and nutrients were greatly increased in the effect area of Yangtze River discharges. Correlations between dissolved inorganic nitrogen, Chl. a and salinity were negative patterns strongly, in contrast, those of inorganic phosphorus, COD and Chl. a were positive, which indicates that phytoplankton biomass and phosphorus are considered as important factors of organic matter distribution and algal growth, respectively. in the study area. The distribution of ignition loss, COD, and $H_2S$ of surface sediment were in the ranges of 2.61-8.81%, $0.64-11.86mgO_2/g-dry$, and ND-0.25 mgS/g-dry, respectively, with relatively high concentration in the eastern part of the study area. Therefore, to effective and sustainable use and management of this area, continuous monitoring and countermeasures about major input sources to the water and sediment, and prediction according to the environmental variation, are necessary.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.283-287
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• 2007

KIER has been developing the anode-supported flat tubular solid oxide fuel cell unit bundle for the intermediate temperature($700{\sim}800^{\circ}C$) operation. Anode-supported flat tubular cells have Ni/YSZ cermet anode support, 8 moi.% $Y_2O_3$ stabilized $ZrO_2(YSZ)$ thin electrolyte, and cathode multi-layer composed of Sr-doped $LaSrMnO_3(LSM)$, LSM-YSZ composite, and $LaSrCoFeO_3(LSCF)$. The prepared anode-supported flat tubular cell was joined with ferritic stainless steel cap by induction brazing process. Current collection for the cathode was achieved by winding Ag wire and $La_{0.6}Sr_{0.4}CoO_3(LSCo)$ paste, while current collection for the anode was achieved by using Ni wire and felt. For making stack, the prepared anode-supported flat tubular cells with effective electrode area of $90\;cm^2$ connected in series with 12 unit bundles, in which unit bundle consists of two cells connected in parallel. The performance of unit bundle in 3% humidified $H_2$ and air at $800^{\circ}C$ shows maximum power density of $0.39\;W/cm^2$ (@ 0.7V). Through these experiments, we obtained basic technology of the anode-supported flat tubular cell and established the proprietary concept of the anode-supported flat tubular cell unit bundle.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.376-383
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• 2022

The current study, which consisted of two independent studies (laboratory and greenhouse), was carried out to project the hypothesis fungi-spray scheduling for leaf mold and gray leaf spot in tomato, as well as to evaluate the effect of temperature and leaf wet duration on the effectiveness of different fungicides against these diseases. In the first experiment, tomato leaves were infected with 1 × 10⁴ conidia·mL^-1 and put in a dew chamber for 0 to 18 hours at 10 to 25℃ (Fulvia fulva) and 10 to 30℃ (Stemphylium lycopersici). In farm study, tomato plants were treated for 240 hours with diluted (1,000 times) 30% trimidazole, 50% polyoxin B, and 40% iminoctadine tris (Belkut) for protection of leaf mold, and 10% etridiazole + 55% thiophanate-methyl (Gajiran), and 15% tribasic copper sulfate (Sebinna) for protection of gray leaf spot. In laboratory test, leaf condensation on the leaves of tomato plants were emerged after 9 hrs. of incubation. In conclusion, the incidence degree of leaf mold and gray leaf spot disease on tomato plants shows that it is very closely related to formation of leaf condensation, therefore the incidence of leaf mold was greater at 20 and 15℃, while 25 and 20℃ enhanced the incidence of gray leaf spot. The incidence of leaf mold and gray leaf spot developed 20 days after inoculation, and the latency period was estimated to be 14-15 days. Trihumin fungicide had the maximum effectiveness up to 168 hours of fungicides at 12 hours of wet duration in leaf mold, whereas Gajiran fungicide had the highest control (93%) against gray leaf spot up to 144 hours. All the chemicals showed an around 30-50% decrease in effectiveness after 240 hours of treatment. The model predictions in present study could be help in timely, effective and ecofriendly management of leaf mold disease in tomato.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.18
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• pp.88-123
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• 1975

To obtain useful fundamental informations for improving cultural practices of barley, an investigation was made on the influences of different fertilizer level and seeding rate as well as seeding date on yield and yield components and their balancing procedure using barley variety Suwon ＃ 18, and at the same time, 8 varieties including Suwon ＃ 18 were also tested to clarify the varietal responses in terms of their yield and yield components under different seeding date at Crop Experiment Station, Suwon, during the period of 1969 and 1970. The results obtained were summarized as follows; 1. Days to emergence of barley variety Suwon ＃ 18 at Suwon, took 8 to 19 days in accordance with given different seeding date (from Sept. 21 to Oct. 31). Earlier emergence was observed by early seeding and most of the seeds were emerged at 15$0^{\circ}C$ cumulated soil temperature at 5cm depth from surface under the favorable condition. 2. Degree of cold injury in different seeding date was seemed to be affected by the growth rate of seedlings and climatic condition during the wintering period. Over growth and number of leaves less than 5 to 6 on the main stem before wintering were brought in severe cold damage during the wintering period. 3. Even though the number of leaves on the main stem were variable from 11 to 16 depending upon the seeding date. this differences were occurred before wintering and less variation was observed after wintering. Particularly, differences of the number of main stem leaves from September 21 to October 11 seeding date were occurred due to the differences of number of main stem leaves before wintering. 4. Dry matter accumulation before wintering was high in early seeded plot and gradually decreased in accordance with delayed seeding date and less different in dry matter weight was observed after wintering. However, the increment rate of this dry matter was high from regrowth to heading time and became low during the ripening period. 5. Number of tillers per $\m^2$ was higher in early seeding than late one and dense planting was higher in the number of tillers than sparse planting. Number of tillers per plant was lower in number and variation in dense planting, and reverse tendency was observed in sparse planting. By increasing seedling rate in early seeding date the number of tiller per plant was remarkably decreased, but the seeding rate didn't affect the individual tillering capacity in the late seeding date. 6. Seedlings were from early planting reached maximum tillering stage earlier than those from the late planting and no remarkable changes was observed due to increased seeding rate. However. increased seeding rate tends to make it earlier the maximum tillering stage early. 7. Stage of maximum tillering was coincided with stage of 4-5 main stem leaves regardless the seeding date. 8. Number of heads per $\m^2$ was increased with increased seeding rate but considerable year variation in number of heads was observed by increased fertilizer level. Therefore, it was clear that there is no difficulties in increasing number of heads per $\m^2$ through increasing both fertilizer level and seeding rate. This type of tendency was more remarkable at optimum seeding time. In the other hand, seeding at optimum time is more important than increasing seeding rate, but increasing seeding rate was more effective in late seeding for obtaining desirable number of heads per $\m^2$. 9. Number of heads per $\m^2$ was decreased generally in all varieties tested in late seeding, but the degree of decrease by late seeding was lower in Suwon ＃ 18. Yuegi, Hangmi and Buheung compared with Suwon ＃ 4, Suwon ＃ 6, Chilbo and Yungwolyukak. 10. Highly significant positive correlations were obtained between number of head and tillers per $\m^2$ from heading date in September 21 seeding, from before-wintering in October 1 seeding and in all growth period from October 11 to October 31 seeding. However, relatively low correlation coefficient was estimated between number of heads and tillers counted around late March to early April in any seeding date. 11. Valid tiller ratio varied from 33% to 76% and highest yield was obtained when valid tiller ratio was about 50%. Therefore, variation of valid tiller ratio was greater due to seeding date differences than due to seeding rate. Early seeding decreased the valid tiller ratio and gradually increased by delaying seeding date but decreased by increasing seeding rate. Among the varieties tested Suwon ＃ 18, Hangmi, Yuegi as well as Buheung should be high valid tiller ratio not only in late seeding but also in early seeding. In contrast to this phenomena, Chilbo, Suwon ＃ 4, Suwon ＃ 6 and Yungwolyukak expressed low valid tiller ratio in general, and also exhibited the same tendency in late seeding date. 12. Number of grains per spike was increased by increasing fertilizer level and decreased by increasing seeding rate. Among the seeding date tested. October 21 (1969) and October 11 (1970) showed lowest number of grains per spike which was increased in both early seeding and late seeding date. There were no definite tendencies observed along with seeding date differences in respective varieties tested. 13. Variation of 1000 grain weight due to fertilizer level applied, seeding date and seeding rate was not so high as number of grains per spike and number of heads per $\m^2$, but exhibited high year variation. Increased seeding rate decreased the 1000 grain weight. Among the varieties tested Chilbo and Buheung expressed heavy grain weight, while Suwon ＃ 18, Hangmi and Yuegi showed comparatively light grain weight. 14. Optimum seeding date in Suwon area was around October 1 to October 11. Yield was generally increased by increasing fertilizer level. Yield decrease due to early seeding was compensated in certain extent by increased fertilizer application. 15. Yield variations due to seeding rate differences were almost negligible compare to the variations due to fertilizer level and seeding date. In either early seeding or law fertilizer level yield variation due to seeding rate was not so remarkable. Increment of fertilizer application was more effective for yield increase especially at increased seeding rate. And also increased seeding rate fairly compensated the decrease of yield in late seeding date. 16. Optimum seeding rate was considered to be around 18-26 liters per 10a at N-P-K=10.5-6-6 kg/10a fertilizer level considering yield stabilization. 17. Varietal differences in optimum seeding date was quite remarkable Suwon ＃ 6, Suwon ＃ 4. Buheung noted high yield at early seeding and Suwon ＃ 18, Yuegi and Hangmi yielded higher in seeding date of October 10. However, Buheung showed late seeding adaptability. 18. Highly significant positive correlations were observed between yield and yield components in all treatments. However, this correlation coefficient was increased positively by increased fertilizer level and decreased by increased seeding rate. Significant negative correlation coefficients were estimated between yield and number of grains per spike, since increased number of heads per m2 at the same level of fertilizer tends to decrease the number of grains per spike. Comparatively low correlation coefficients were estimated between 1000 grain weight and yield. 19. No significant relations in terms of correlation coefficients was observed between number of heads per $\m^2$ and 1000 grain weight or number of grains per head.

• Microbiology and Biotechnology Letters
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• v.8 no.3
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• pp.181-191
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• 1980

For the purpose of studies on the citric acid production, some experiments were carried out with isolated strains. The results obtained were as follows. 1) The optimal culture media of the strain M-80 in surface culture contained 140g of sucrose, 3.0g of (N $H_4$)$_2$S $O_4$, 1.5g of K $H_2$P $O_4$, 0.2g of MgS $O_4$.7$H_2O$, 3.0mg of F $e^{++}$, 1.0mg of Z $n^{++}$, 0.5N HCI to a pH of 5.0 and distilled water to 1.0 liter; and that of the strain M-315 in surface culture contained 140g of sucrose, 2.0g of N $H_4$N $O_3$, 1.0g of K $H_2$P $O_4$, 0.25g of MgS $O_4$. 7$H_2O$, 2.0mg of F $e^{++}$, 2.0mg of Z $n^{++}$, 0.05mg of C $u^{++}$, 0.5N HCI to a pH of 4.5 and distilled water to 1.0 liter. While that of the strain M-315 in submerged culture contained 140g of sucrose, 2.5g of N $H_4$N $O_3$, 1.5g of K $H_2$P $O_4$, 0.3g of MgS $O_4$. 7$H_2O$, 3.0mg of F $e^{++}$, 0.1mg of C $u^{++}$, 0.5N HCI to a pH of 4.5 and distilled water to 1.0 liter. The optimal temperature and size of inoculum were mostly 28-3$0^{\circ}C$, 10$^{7}$ -10$^{8}$ spores/50ml, respectively. 2) Through the course of citric acid production, the growth of strains had nearly been completed, pH value was rapidly decreased below 2.0 and the content of sugar was also reduced, while the accumulation of citric acid in media was remarkably begun in about 3-4 days. The yields of citric acid generally reached the maximum level in 8-10 days in surface or submerged fermentation process. 3) Methanol was effective citric acid production when they were added to fermentation media. In the case of surface culture, by addition of 2％ (strain M-80), 3％ (strain M-315), the yields of citric acid was increased 6.5％, 20.6%, respectively and 5.0% yield was increased by addition of 3% methanol in submerged culture media of the strain M-315. 4) Chromatography analysis of culture broth after fermentation under optimal culture conditions detected that the majority of acid in media was citric acid. 72.1mg/ml, 98.1mg/ml, of citric acid were determined in surface culture media by strains of M-80, M-315, and 59.8 mg/ml of citric acid was contained in the submerged culture media by the strain M-315. strain M-315.

• Journal of the Korean Wood Science and Technology
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• v.7 no.2
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• pp.3-30
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• 1979

Larch ($\underline{Larix}$ $\underline{leptolepis}$ GORDON), one of the major afforestation species in Korea in view of its growing stock and rate of growth, is not favored as a raw material for pulp due to its low yield of pulp and difficulties with bleaching arising from the high content of extractives in wood, and the high heartwood ratio and the active phenolics, respectively. The purpose of this study is to investigate the characteristics of firstly pulping with various additives of cellulose protector for the yield of pulp, and secondly bleaching with oxygen for chlotination-alkali extraction of five stage-sequence to reduce chlorine compounds in bleaching effluents. The kraft cooking liquor for five age groups of larchwood was 18 percent active alkali with 25 percent sulfidity and 5 : 1 liquor-to-wood ratio, and each soda liquor for sap-and heart-wood of the 15-year-old larchwood was 18 percent alkali having one of the following cellulose protectors as the additive; magnesium sulfate ($MgSO_4$, 2.5%), zinc sulfate ($ZnSO_4$, 2.5%), aluminium sulfate ($Al_2(SO_4)_3$, 2.5%), potasium iodide (KI, 2.5%), hydroquinone (HQ, 2.5%), anthraquinone (AQ, 0.1%) and ethylene diamine (EDA, 2.5%). Then each anthraquinone-soda liquor for the determination of suitable cooking condition was the active alkali level of 15, 17 and 19 percent with 1.0, 0.5 and 0.1 percent anthraquinone, respectively. The cooking procedure for the pulps was scheduled to heat to 170$^{\circ}C$ in 90 minutes and to cook 90 minutes at the maximum temperature. The anthraquinone-soda pulps from both heartwood and sapwood of 15-year-old larchwood prepared with 0.5 percent anthraquinone and 18 percent active alkali were bleached in a four-stage sequency of OCED. (O: oxygen bleaching, D: chlorine dioxide bleaching and E: alkali extraction). In the first stage oxygen in atmospheric pressure was applied to a 30 percent consistency of pulp with 0.1 percent magnesium oxide (MgO) and 3, 6, and 9 percent sodium hydroxide on oven dry base, and the bleached results were compared pulps bleached under the conventional CEDED (C: chlorination). The results in the study were summarized as follows: 1. The screened yield of larch kraft pulp did not differ from particular ages to age group, but heartwood ratio, basic density, fiber length and water-extractives contents of wood and the tear factor of the pulp increased with increasing the tree age. The total yield of the pulp decreased. 2. The yield of soda pulp with various chemicals for cellulose protection of the 15-year-old larchwood increased slightly more than that of pure soda pulp and was slightly lower than that of kraft pulp. The influence of cellulose protectors was similar to the yield of pulps from both sapwood and heartwood. The effective protectors among seven additives were KI, $MgSO_4$ and AQ, for which the yields of screened pulp was as high as that of kraft pulp. Considering the additive level of protector, the AQ was the most effective in improving the yield and the quality of pulp. 3. When the amount of AQ increased in soda cooking, the yield and the quality of the pulp increased but rejects in total yield increased with decreasing the amount of active alkali from 19 to 15 percent. The best proportion of the AQ seemed to be 0.5 percent at 17 percent active alkali in anthraquinone-soda pulping. 4. On the bleaching of the AQ-soda pulp at 30 percent consistency with oxygen of atomospheric pressure in the first stage of the ODED sequence, the more caustic soda added, the brighter bleached pulp was obtained, but more lignin-selective bleaching reagent in proportion to the oxygen was necessary to maintain the increased yield with the addition of anthraquinone. 5. In conclusion, the suitable pulping condition for larchwood to improve the yield and quality of the chemical pulp to the level for kraft pulp from conventional process seemed to be. A) the selection of young larchwood to prevent decreasing in yield and quality due to the accumulation extractives in old wood, B) the application of 0.5 percent anthraquinone to the conventional soda cooking of 18 percent active alkali, and followed, C) the bleaching of oxygen in atmospheric pressure on high consistency (30%) with 0.1 percent magnesium oxide in the first stage of the ODED sequence to reduce the content of chlorine compounds in effluent.