• Microbiology and Biotechnology Letters
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• v.51 no.3
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• pp.257-267
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• 2023

The potential polyhydroxyalkanoates (PHA)-producing bacteria, Bacillus megaterium PP-10, was successfully isolated and studied its feasibility for utilization of pineapple peel waste (PPW) as a cheap carbon substrate. The PPW was pretreated with 1% (v/v) H₂SO₄ under steam sterilization and about 26.4 g/l of total reducing sugar (TRS) in pineapple peel hydrolysate (PPH) was generated and main fermentable sugars were glucose and fructose. A maximum cell growth and PHA concentration of 3.63 ± 0.07 g/l and 1.98 ± 0.09 g/l (about 54.58 ± 2.39%DCW) were received in only 12 h when grown in PPH. Interestingly, PHA productivity and biomass yield (Y_x/s) in PPH was about 4 times and 1.5 times higher than in glucose. To achieve the highest DCW and PHA production, the optimal culture conditions e.g. carbon to nitrogen ratios of 40 mole/mole, incubation temperature at 35℃ and shaking speed of 200 rpm were performed and a maximum DCW up to 4.24 ± 0.04 g/l and PHA concentration of 2.68 ± 0.02 g/l (61% DCW) were obtained. The produced PHA was further examined its monomer composition and found to contain only 3-hydroxybutyrate (3HB). This finding corresponded with the presence of class IV PHA synthase gene. Finally, certain thermal properties of the produced PHA i.e. the melting temperature (T_m) and the glass transition temperature (T_g) were about 176℃ and -4℃, respectively whereas the M_w was about 1.07 KDa ; therefore, the newly isolated B. megaterium PP-10 is a promising bacterial candidate for the efficient conversion of low-cost PPH to PHA.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.9
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• pp.1305-1313
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• 2006

Five male dairy goats (Saanen), 4.6 month old with a body weight of 21.4 ($SD{\pm}1.6$) kg, were used to examine 5 dietary urea treatments in a $5{\times}5$ Latin Square experimental design. The five levels of urea were 10, 20, 30, 40 and 50 g urea/kg DM of steam-treated oil palm fronds (OPF) and dry matter intake tended (p>0.05) to increase with increasing urea supplementation up to 30 g/kg OPF (77.7 g/kg $BW^{0.75}$), but decreased (p<0.05) with 40 and 50 g urea/kg OPF (67.4 and 63.7 g/kg BW0.75, respectively) supplementation. Similarly, dry matter, organic matter, crude protein, neutral detergent fiber and hemicellulose digestibilities increased (p<0.05) with the addition of urea to 30 g/kg OPF but thereafter decreased (p<0.05) with 40 and 50 g/kg OPF. Ruminal pH, ruminal $NH_3$-N concentration and plasma urea concentration increased linearly (p<0.01) and quadratically (p<0.01) as a consequence of addition of urea to the diet. Excretion of total purine derivatives (PD) by goats fed 30 g of urea/kg OPF was highest (p<0.05) followed by goats fed 20, 40, 10 and 50 g of urea/kg OPF. Microbial N (g N/day) and efficiency of microbial N supply expressed as g N/kg organic matter apparently digested in the rumen were higher (p<0.05) in goats fed 30 g of urea/kg OPF (5.5 g N/day and 22.0 g N/kg DOMR, respectively) than in goats on 10 and 50 g of urea/kg OPF treatments. However, the former did not differ from goats fed 20 g of urea/kg OPF (3.9 g N/day and 16.6 g N/kg DMOR, respectively). Ruminal VFA concentration, protein/energy ratio, N absorption and N retention increased (p<0.05) with the addition of urea to the diet up to 30 g/kg OPF but decreased (p<0.05) with 40 and 50 g/kg OPF. This implies that the optimal level of urea supplementation in an OPF based diet was about 30 g urea/kg OPF.

• Nuclear Engineering and Technology
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• v.24 no.2
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• pp.154-162
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• 1992

Two major goals for chemical cleaning on the secondary side of nuclear steam generators are to remove sludge effectively and to minimize corrosion of base metals. In this work, electrochemical and sludge dissolution behaviors have been investigated in order to find out which parameters are critical and important during a copper removal process for chemical cleaning and to evaluate safety aspects and effectiveness of two major copper removal processes developed commercially in foreign countries. Hydrogen peroxide is vert effective for the process to use EDTA, NH$_4$OH and EDA at 38$^{\circ}C$ to control the potential of copper in a potential range sood for copper sludge removal. Corrosion rates for carbon steel SA 285 Gr.C and Alloy 600 are very small during this process if it is controlled properly. However, the corrosion rate of SA 285 Gr.C will be increased greatly if its corrosion potential is maintained below -450mV. The process to use EDA and ammonium carbonate is effective at 6$0^{\circ}C$ to dissolve copper sludge if the corrosion potential of copper can be controlled above -200mV. However, it is very difficult to raise the corrosion potential of copper to this range by air blowing and stirring.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.2
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• pp.107-117
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• 1975

Alaska pollack caught in the Northern Pacific Ocean and frozen aboard vessel are skipped to the plant and processed into frozen fillets. In the present paper quality changes during thwaing, refreezing and storage at $-20^{\circ}C$ are discussed. Natural, running-water, vacuum and steam thawing were employed as thawing methods. And contact plate, air blast, immersion in dry ice-alcohol solution freezing and storage at $-5^{\circ}C$ were applied to refreeze the thawed fillets. As quality factors content of drip released, salt-extractable protein, VBN, DNA in the drip and pH were determined. In addition, bacteriological tests were also carried out along with the whole process. In thawing of round material, the vacuum thawing was more effective than any other method, resulting in drip, salt-extractable protein $(N\%)$, VBN and DNA as $4.4\%,\;1.82\%,\;16.21mg\%$ and $13.70\;{\mu}g/ml$, respectively. Storage at $-5^{\circ}C$ as refreezing method yielded lower in drip and DNA content but similar to or slightly higher in both salt-extractable protein and VBN, which might postulate that the quality of the frozen fillet depends not largely on the secondary freezing but on the conditions of thawing and primary freezing. It seemed that most of the bacterial flora in thawed fillet came from skin and viscera of fish, worker's hands, utensils and other processing facilities, since sanitary indicative bacteria were not detected in the frozen flesh of round Alaska pollack. Bacterial quality of fillet varied with thawing methods, vacuum thawing appeared more sanitative compared with other methods as natural, running-water, and steam thawing. Bacterial colonies isolated from the thawed fillet were composed of $73.8\%$ Gram negative rod shape, $4.9\%$ Gram positive rod shape, $18.0\%$ cocci, and $3.3\%$ yeast. Decreasing rate of coliform group of the fillet during the storage at $-20^{\circ}C$ for 30 days was more than $70\%$ and that of plate count was less than of coliform group.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.3
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• pp.395-399
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• 1999

Three experiments were conducted to determine the effects of conditioning a complex (20% whey, 10% lactose, 4% plasma protein, 4% wheat gluten and 2% blood meal) diet on growth performance of weanling pigs. In Exp. 1,180 pigs (average initial BW of 6.4 kg) were fed the experimental diet (1.7% lysine) during a 7-d growth assay. Treatments were a meal control (M), standard (ST), and expander (EX) conditioned mash or pellets. Rate and efficiency of gain were decreased by 39% and 21% (p<0.005) respectively, for pigs fed EX diets compared to those fed the ST diet. In Exp. 2,196 pigs (average initial BW of 6.5 kg) were used to determine the effects of EX operating conditions on nutritional value of a pelleted complex diet. When steam conditioning temperature (prior to expanding) was $54^{\circ}C$, increasing cone pressure of the EX from 0 to 7 to 14 kg/cm2 resulted in linear decreases in rate of gain of weaned pigs (p<0.006), suggesting heat damage of the diet. Increasing conditioning temperature (i.e., adding steam) of the diets from 46 to 54 to $63^{\circ}C$ (cone pressure at $12kg/cm^2$) resulted in improved rate of gain (p<0.04) of the pigs. However, none of the pigs fed expanded diets compared favorably to the pigs fed the conditioned $(54^{\circ}C)$ pellets processed with no cone pressure. In Exp. 3,168 pigs (average initial BW of 6.6 kg) were used to determine the effects of expanding the various components of the diet. Treatments were M and ST pellets as controls, EX-corn, EX-corn soybean-meal, EX corn-soybean meal-oil, and EX-complete diet. Efficiency of gain was increased by 13% with EX portions of the diet compared to the mash control, but there was a marked decrease in performance when the complete diet was expanded (p<0.001). Expanded corn-soybean meal-oil supported the greatest ADG with a 19% increase compared to the average of the EX corn and EX corn-soybean meal treatments (p<0.005). In conclusion, our results suggest no benefit from expanding complete phase-I diets.

• Nuclear Engineering and Technology
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• v.52 no.7
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• pp.1396-1408
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• 2020

Filtered containment venting system (FCVS) is one of the severe accident mitigation systems designed to release containment pressurization to maintain its integrity. The thermal-hydraulic behaviors in FCVSs are important since they affect the operation characteristics of the FCVS. In this study, a representative FCVS was modeled by RELAP5/Mod3.3 code, and the Station BlackOut (SBO) was chosen as an accident scenario. The thermal-hydraulic behaviors of an FCVS during long-term operation with two venting strategies (open-and-close strategy, open-and-non-close strategy) and the sensitivity analysis of important parameters were investigated. The results show that the FCVS can operate up to 250 h with a periodic open-and-close strategy during an SBO. Under the combined effects of steam condensation and water evaporation, the solution inventory in the FCVS increases during the venting phase and decreases during the intermission phase, showing a periodic pattern. Under this condition, the appropriate initial water level is 3-4 m; however, it should be adjusted according to the environment temperature. The FCVS can accommodate a decay heat power of 150-260 kW and may need to feed water for a higher decay heat power or drain water for a lower decay heat power during the late phase. The FCVS can function within an opening pressure range from 450 kPa to 500 kPa and a closing pressure range between 250 kPa and 350 kPa. When the open-and-non-close strategy is adopted, the solution inventory increases quickly in the early venting phase due to steam condensation and then decreases gradually due to the evaporation of water; drying-up may occur in the late venting phase. Decreasing the venting pipe diameter and increasing the initial water level can mitigate the evaporation of the scrubbing solution. These results are expected to provide useful references for the design and engineering application of FCVSs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1881-1888
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• 2014

Pre-thermal treatment is important to minimize quality changes during main cooking or storage. In this study, to optimize pre-thermal treatment of carrots, three types of pre-thermal treatments were applied to carrots and quality changes such as physicochemical, nutritional, or sensory properties were observed. Washed and sliced carrots were thermally treated by hot-water immersion ($100^{\circ}C$, 1~10 min), steaming ($100^{\circ}C$, 1~10 min), and stir-frying with oil (10~80 sec). Carrot tissue was maintained until 2 min hot-water immersion or steaming, and they were damaged by just 30 sec of stir-frying. Color and hardness were significantly affected by treatment time and temperature. Color was completely changed after 5 min and 7 min by hot-water and steam treatments, respectively. Hardness decreased to 44% compared with fresh carrot (4,500 g) after 1 min, 3 min, and 20 sec of hot-water, steam, and stir-frying, respectively. For nutritional changes, ascorbic acid, organic acid, and peroxide activity were reduced by all treatments compared with fresh carrot. Especially, succinic acid was dramatically reduced by hot-water treatment. Otherwise, free sugar contents were increased with greater treatment time in all samples. In this study, pre-thermal treatment of carrot was optimal at 2 min steaming treatment.

• Clean Technology
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• v.18 no.4
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• pp.426-431
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• 2012

Carbon-rich coal can be utilized as a fuel for direct carbon fuel cell (DCFC). However, left-behind ash after the electrochemical oxidation may hinder the electrochemical reactions. In this study, we produced ash-free coal (AFC) by thermal extraction and then tested it as a fuel for DCFC. DCFC was built based on solid oxide electrolyte and the electrochemical performance of AFC mixed with $K_2CO_3$ was compared with AFC only. Significantly enhanced power density was found by catalytic steam gasification of AFC. However, an increase of the power density by catalytic pyrolysis was negligible. This result indicated that a catalyst activated the steam gasification reactions, producing much more $H_2$ and thus increasing the power density, compared to AFC only. Results of a quantitative analysis showed much improved kinetics in AFC with $K_2CO_3$ in agreement with DCFC results. A secondary phase of potassium on yttria-stabilized zirconia (YSZ) surface was observed after the cell operation. This probably caused poor long-term behavior of AFC with $K_2CO_3$. A thin YSZ (30 ${\mu}m$ thick) was found to be higher in the power density than 0.9 mm of YSZ.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.6
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• pp.1231-1244
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• 2014

Oysters, especially are excellent source of several mineral including iron, zinc and selenium, which are often low in the mordern diet. They are also an excellent source of glycogen, vitamin B12 and considered the healthiest when eaten raw on the half shell in good tasted season from November to March. This study was investigated for the purpose of obtaining basic data which can be applied to processing of two kinds of canned boiled oyster (canned boiled oyster, canned boiled oyster in bamboo salt). Shucked oyster meat was cooked in steam (15min) after washing with water, filled 90g into can (301-3), added with salt solution and then precooked for 10 min. at $100^{\circ}C$. Canned boiled oyster was added 1.5% salt solution 60mL. Canned boiled oyster in bamboo salt was added 0.5% salt solution 30mL and 0.7% bamboo salt solution 30mL. The cans were seamed using a vacuum seamer, and then sterilized for various Fo values (Fo 8~12 min.) in a steam system retort at $116^{\circ}C$, $118^{\circ}C$. Viable bacterial count, proximate composition, pH, salinity, yield, VBN, amino-N, TBA, mineral, color value, free amino acid, hardness and sensory evaluation of two kinds of canned boiled oyster produced at various sterilization condition (Fo 8~12 min.) were measured after divide to meat and juice. The results showed that canned boiled oyster in bamboo salt sterilized at Fo 8 min. was the most desirable because this condition is the most economical and tasty.

• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.61-68
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• 2021

Experiments of vertically upward steam-water two-phase flow have been carried out in single-side heated narrow rectangular channel with a gap of 3 mm. Flow patterns were identified and classified through visualization directly. Slug flow was only observed at 0.2 MPa but replaced by block-bubble flow at 1.0 MPa. Flow pattern maps at the pressure of 0.2 MPa and 1.0 MPa were plotted and the difference was analyzed. The experimental data has been compared with other flow pattern maps and transition criteria. The results show reasonable agreement with Hosler's, while a wide discrepancy is observed when compared with air-water two-phase experimental data. Current criteria developed based on air-water experiments poorly predict bubble-slug flow transition due to the different formation and growth of bubbles. This work is significant for researches on heat transfer, bubble dynamics and flow instability.