• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.752-759
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• 2014

Varieties of research on turbulent-induced noise is conducted with combinations of acoustic analogy methods and computational fluid dynamic methods to analyze efficiently and accurately. Application of FW-H acoustic analogy without turbulent noise is the most popular method due to its calculation cost. In this paper, turbulent-induced noise is predicted using RANS turbulence model and permeable FW-H method. For simplicity, noise from 2D cylinder is examined using three different methods, direct method of RANS, FW-H method without turbulent noise and permeable FW-H method which can take into account of turbulent-induced noise. Turbulent noise was well predicted using permeable FW-H method with same computational cost of original FW-H method. Also, ability of permeable FW-H method to predict highly accurate turbulent-induced noise by applying adequate permeable surface is presented. The procedure to predict turbulent-induced noise using permeable FW-H is established and its usability is shown.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.3
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• pp.195-207
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• 2000

Organic and inorganic characteristics including bacterial cell number, enzyme activity, nutrients, and heavy metals have been monitored in twelve acrylic experimental tanks for two weeks to estimate and compare self-purification capacities in two Korean wet-land environments, tidal flat and rice field, which are possibly different with the environments in other countries because of their own climatic conditions. FW tanks, filled with rice field soils and fresh water, consist of FW1&2 (with paddy), FW3&4 (without paddy), and FW5&6 (newly reclaimed, without paddy). SW tanks, filled with tidal flat sediments and salt water, are SW1&2 (with anoxic silty mud), SW3&4 (anoxic mud), and SW5&6 (suboxic mud). Contaminated solution, which is formulated with the salts of Cu, Cd, As, Cr, Pb, Hg, and glucose+glutamic acid, was spiked into the supernatent waters in the tanks. Nitrate concentrations in supernatent waters as well as bacterial cell numbers and enzyme activities of soils in the FW tanks (except FW5&6) are clearly higher than those in the SW tanks. Phosphate concentrations in the SW1 tank increase highly with time compared to those in the other SW tanks. Removal rates of Cu, Cd, and As in supematent waters of the FW5&6 tanks are most slow in the FW tanks, while the rates in SW1&2 are most fast in the SW tanks. The rate for Pb in the SW1&2 tanks is most fast in the SW tanks, and the rate for Hg in the FW5&6 tanks is most slow in the FW tanks. Cr concentrations decrease generally with time in the FW tanks. In the SW tanks, however, the Cr concentrations decrease rapidly at first, then increase, and then remain nearly constant. These results imply that labile organic materials are depleted in the FW5&6 tanks compared to the FW1&2 and FW3&4 tanks. Removal of Cu, Cd, As from the supernatent waters as well as slow removal rates of the elements (including Hg) are likely due to the combining of the elements with organic ligands on the suspended particles and subsequent removal to the bottom sediments. Fast removal rates of the metal ions (Cu, Cd, As) and rapid increase of phosphate concentrations in the SW1&2 tanks are possibly due to the relatively porous anoxic sediments in the SW1&2 tanks compared to those in the SW3&4 tanks, efficient supply of phosphate and hydrogen sulfide ions in pore wates to the upper water body, complexing of the metal ions with the sulfide ions, and subsequent removal to the bottom sediments. Organic materials on the particles and sulfide ions from the pore waters are the major factors constraining the behaviors of organic/inorganic elements in the supernatent waters of the experimental tanks. This study needs more consideration on more diverse organic and inorganic elements and experimental conditions such as tidal action, temperature variation, activities of benthic animals, etc.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.419-425
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• 2004

Two different groups (30 and 60 inds.) of olive flounder (Paralichthys olivaceus) were abruptly (within 30 min) exposed to hypo-salinities from seawater (SW, 35$\textperthousand$) to freshwater (FW, 0$\textperthousand$) (30FW and 60FW) and to 35$\textperthousand$ (30SW and 60SW) in a flow through seawater culture systems. Analysis of plasma samples showed the following significant increase at 0$\textperthousand$: cortisol from $2.8\;ng\;mL^{-1}$ to $66.9\;ng\;mL^{-1}$ (30FW) and from $2.7\;ng\;mL^{-1}$ to $314.1\;ng\;mL^{-1}$ (60FW) after 24 hours of exposure; glucose from $15.8\;mg\;dL^{-1}$ to $257.7\;mg\;dL^{-1}$ after 3 hours exposure and to $164.0\;mg\;dL^{-1}$ after 24 hours in 60FW. Plasma $Na^+$ concentration of 30FW and 60FW were decreased until 24 hours after expose. However that in 30SW and 60SW showed no significant differences. Plasma $Cl^-$ concentration of 60FW was decreased from $59.0\;mEq\;L^{-1}$ to $43.5\;mEq\;L^{-1}$ and to $30.0\;mEq\;L^{-1}$ after 3 and 24 hours of exposure, respectively. At all experimental groups, survival were 100% until 24 hours.

• Journal of Biosystems Engineering
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• v.37 no.5
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• pp.302-313
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• 2012

Purpose: The biogas productivity potential of fish waste (FW) was evaluated. Methods: Batch trials were carried out in 1.3 L glass digesters kept in a temperature controlled chambers at $36.5^{\circ}C$. The first order kinetic model and the modified Gompertz model were evaluated for biogas production. The Chen and Hashimoto model was used to determine the critical hydraulic retention time (HRT $_{Critical}$) for FW under mesophilic conditions. The feasibility of co-digestion of FW with animal manure was studied. Results: The biogas and methane potential of FW was found to be 757 and 554 mL/g VS, respectively. The methane content in the biogas produced from FW was found to be 73% and VS removal was found to be 77%. There was smaller difference between measured and predicted biogas production when using the modified Gompertz model (16.5%) than using first order kinetic model (31%). The time period for 80%-90% of biogas production ($T_{80-90}$) from FW was calculated to be 50.3-53.5 days. Similarly, the HRT $_{Critical}$ for FW was calculated to be 13 days under mesophilic conditions. The methane production from swine manure (SM) and cow manure (CM) digesters could be enhanced by 13%-115% and 17%-152% by mixing 10%-90% of FW with SM and CM, respectively. Conclusions: The FW was found to be highly potential substrate for anaerobic digestion for biogas production. The modified Gompertz model could be more appropriate in describing anaerobic digestion process of FW. It could be promising for co-digestion of FW with animal manure.

• Food Science and Preservation
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• v.31 no.1
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• pp.112-125
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• 2024

This study determined the relationships between the total anthocyanin content in apple skin and the total polyphenols, flavonoids, proanthocyanidins, and soluble solids contents in the flesh of cold-stored Fuji apples. Total anthocyanin content in apple skin ranged from 0.130±0.005 mg CE/g fw to 0.262±0.028 mg CE/g fw, and the overall average was 0.200±0.008 mg CE/g fw. The total polyphenolic compounds in the flesh was ranged from a 4.283±0.141 mM GAE/g fw to 8.207±0.234 mM GAE/g fw, and the average content was 6.275±0.177 mM GAE/g fw. The total flavonoid content ranged from 4.510±0.080 mM QE/g fw to 2.467±0.458 mM QE/g fw, and the average total flavonoid content was about 3.586 mM QE/g fw. The total proanthocyanidin content was relatively high, ranging from 3.475±0.577 mM EE/g fw to 6.816±0.277 mM EE/g fw, and the soluble solid in the flesh was about 12 °Brix to 14 °Brix. The DPPH radical scavenging activity of extracts from apple flesh ranged from 66.36% to 94.99%, and the ascorbate equivalent concentration was 0.482 mM. The ABTS radical scavenging activity was 99.12% to 99.9%, indicating a higher inhibitory activity than the DPPH inhibitory activity, and the ascorbate equivalent concentration was 0.486 mM. The correlation between the total anthocyanin and total polyphenolic compounds was y = 15.192x + 3.2169 (R²=0.2748), but the concentration of total polyphenolic compounds increased when the total anthocyanin content was increased. The correlation equation of total anthocyanin with total flavonoids was y = 15.18x + 0.5555 (R²=0.6226), with total proanthocyanin was y = 14.918x + 2.3422 (R²=0.3372), and with soluble solid was y = 10.558x + 11.126 (R²=0.1925), indicating that the correlation of total anthocyanin with total flavonoid was higher than that with soluble solid.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.569-569
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• 2016

본 연구에서는 소유역 내 오염원 현황에 따른 발생부하와 배출부하를 분석하고자 하였다. 대상유역은 경상북도 영천시 북안천 일대이며, 소유역을 6개의 세유역으로 구분하여 발생부하와 배출부하를 산정하였다. 오염원 현황자료는 2013년 전국오염원 조사자료를 기초로 하였으며, 행정구역 단위의 오염원 조사 및 행정구역과 유역의 경계가 일치 하지 않는 경우의 오염원별 점유율은 토지종합정보망(Land Management Information System, LMIS)의 연속지적도 자료를 이용하여 면적비로 산정하였다. 대상유역의 전체 인구는 총 5,140명이며, 이 중 시가 인구가 2명, 비시가 인구가 5,138명으로 나타났다. 생활계 오염원은 소유역 별 인구를 분석한 결과, FW-'1은 3,113명, FW-'2는 298 명, FW-'3은 604 명, FW-'4는 836 명, FW-'5는 283 명, 그리고 FW-'6은 6 명으로 분석되었다. FW-'1의 인구는 총 3,113명으로 대상유역에서 가장 많은 인구가 분포하고 있는 것으로 나타났다. 축산계 오염원은 FW-'1 지점에 총 115 가구의 농가가 위치하여 소유역 중 가장 많은 축산 농가가 위치하고 있으며. 가축 사육 두수는 돼지 8,040두, 젖소 394두, 한우 1,587두, 사슴 10두 그리고 가금(기타) 수가 292,158두로 다른 지점들과 비교하여 사육 두수가 가장 많은 것으로 나타났다. FW-'2 지점은 돼지 1,350두가 있는 돼지 농가가 1가구 위치하고 있는 것으로 나타났다. FW-'3 지점은 돼지 14,692두, 한우 1,287두, 가금(기타) 100두가 있으며, 축산 농가는 총 42가구가 위치하고 있는 것으로 나타났다. 다른 지점들과 비교하여 돼지 사육 두수가 가장 많은 것으로 나타났다. FW-'4 지점의 가축현황은 돼지가 900마리, 한우 1,222 마리이며, 총 57개의 농가가 위치하고 있고, 이 중 돼지 농가는 1가구이며, 그 외 56개의 농가는 모두 한우 농가이다. FW-'5 지점은 한우 407마리 가금(기타) 150마리가 있는 것으로 나타났으며, FW-'6 지점은 축산 농가가 존재하지 않는다. 또한 대상유역 내에는 총 14개의 산업체가 있으며, $800.33m^3/day$만큼의 폐수를 발생시키고 있다. 이중 FW-'1 지점 산업체 개수는 12개이며, 폐수 발생량은 $730.59m^3/day$로 가장 많은 양의 폐수가 발생하고 있다. 대상유역 내에는 산업계, 양식계, 매립계의 오염원은 없는 것으로 나타났다. 오염원 자료를 바탕으로 발생부하량과 배출부하량 산정결과 생활계와 축산계, 토지계 중축산계의 BOD, T-N, T-P 모두 가장 높은 것으로 분석되었다. 배출부하량 비교 결과에서도 BOD, T-N, T-P 모두 축산계 배출부하량의 비율이 높게 나타났으며, 이 중 BOD는 토지계 배출부하량이 차지하는 비율이 축산계 배출부하량보다 약간 높게 나타났다. T-N과 T-P는 축산계 배출부하량 비율이 가장 높은 것으로 분석되었다. 그러나 오염원의 정량적인 발생원 규명을 위해서는 오염원 그룹이 포함되어있는 지역에 대하여 장기적인 실측 모니터링을 통해 얻은 오염부하를 산정하여 비교?분석하는 연구가 필요할 것으로 판단된다.

• Food Science of Animal Resources
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• v.37 no.5
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• pp.690-697
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• 2017

Despite the benefits associated with the use of food waste (FW), there are mixed consumer perceptions regarding pork quality harvested from pigs fed FW. Twenty crossbred pigs were selected for the present study. Ten pigs were fed a conventional diet (control group), and the other 10 pigs were given a conventional diet and FW (FW group) during different growth stages. Meat quality in the FW group showed deteriorative qualities with higher lightness and yellowness synonymous to pale soft exudative meat. Drip loss in the experimental group was significantly higher than that in the control group (p<0.01). The contents of polyunsaturated fatty acids in the FW group were higher and those of saturated and monounsaturated fatty acids were lower than those in the control group. The contents of thiobarbituric acid were significantly different between the control and FW groups (p<0.05). There was also a significant difference between the control and FW groups in terms of off-flavor (p<0.05) after sensory evaluation. To conclude, the off-flavor noted, including other inferior pork quality traits, in the FW group implies that FW should not be used as swine feed.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.416-421
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• 2001

This paper presents the numerical prediction of sound generated by viscous flow past a circular cylinder. The two dimensional flow field is predicted using FEM based Reynolds-averaged Navier-Stokes solver, and the calculated unsteady fluid field values are utilized by an acoustic code that implements Ffowcs Willianms-Hawkings(FW-H) equation. The integration surface used in acoustic analysis is extended from the cylinder surface to permeable surfaces. The 2D based CFD calculations overpredict the acoustic amplitude, however, if adequate correlation length is used, the predicted acoustic amplitude agrees well with experiment. The predictions using extended integral surface in FW-H equation show results that contain the characteristics of quadrupole - volume integration - noise term, and do not vary seriously with the integral surface location.

• Korean Journal of Poultry Science
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• v.32 no.4
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• pp.281-289
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• 2005

This study investigated the effect of dried food-waste diets(FW) fermented by Aspergillus oryzae(AO), on broiler growth performance, $NH_3$, emission and fecal microflora. Three hundreds broilers, two week old Hubbard strain, were randomly allotted to 4 experiments and fed with standards early boiler diet replaced with FW and AFW. In experiment 1, eighty four broilers were distributed into 7 treatments with 4 pens at 3 birds per replicate(pen). The dietary treatments ; T1 was com-soy bean meal based broiler diet(Control), T2, T3, T4 were for basal diet replaced with dried food waste without AO(FW) at the level of 20, 40 and $60\%$, respectively and T5, T6 and T7 followed the same levels for the basal diet but using Aspergillus oryzae inoculate food-waste(AFW). For experiments 2, 3, 4, seventy two broilers were distributed into 6 treatments with 4 pens at 3 birds per replicate(pen), respectively. The dietary treatments were the com-soy bean meal based broiler diet replacement with different combinations of FW and AFW, 1:0, 3:1, 1:1, 1:3, 0:1. at level of 20, 40 and $60\%$, respectively. In Exp. 1, it tended to be decreased in weight gain, however, there were no statistical differences among treatments except FW $60\%$ level of replacement(p<0.05). Feed intake and feed efficiency was not different among treatments. Total bacterial counts were not different between the control and FW diet, but E. coli decreased as the AFW levels of replacement were increased(p<0.05). There were no differences in weight gain, feed intake and feed efficiency among treatments in Exp. 2 and weight gains were lower fur FW diet compared with the control and AFW diet in Exp. 3(p<0.05). In Exp. 4, there were no differences in feed intakes among treatments, but lower in weight gain and feed efficiency in FW diet than that the control. In experiment 3, the $NH_3$ emission was the highest among treatments in FW/AFW 1:0 diet(p<0.05). From these results, it seems that FW would be supplemented up to $20\%$ in broiler diets and AO culture extract could improve FW value as feed supplements.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.299-306
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• 2005

Anaerobic fermentation of food waste (FW) and waste activated sludge (WAS) for hydrogen production was performed in CSTR (Continuous Stirred tank reactor) under various HRTs and volumetric mixing ratio (V/V) of two substrates, FW and WAS. The specific hydrogen production potential of FW was higher than that of WAS. However, pH drop in the CSTR for hydrogen production from FW was higher than that from WAS. The maintenance of desired pH during fermentative hydrogen production is regarded as the most important operation parameter for the stable hydrogen production. Therefore, when the potential of hydrogen production from FW and better buffer capacity of WAS, the proper mixture of FW and WAS for fermentative hydrogen production were considered as a useful complementary substrate. The maximum yield of specific hydrogen production, 140 mL/g VSS, was found at HRT of 2 day and the volumetric mixing ratio of 20:80 (WAS : FW). The spatial distribution of hydrogen producing bacteria was observed in anaerobic fermentative reactor using fluorescent in situ hybridization (FISH) method.