• Journal of Aquaculture
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• v.6 no.3
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• pp.187-197
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• 1993

Studies related to water quality in catfish ponds were conducted on commercial catfish production ponds and compared with its receiving streams' water quality in central and west-central Alabama. The ponds were stocked with 10,000 fish/ha. The ponds were aerated nightly (0000-0600 hrs). Fish were fed to satiation at about the same time, six-days a week. In order to assess the pollutional strength of effluents from commercial channel catfish ponds, water samples were collected during each calender season from fall 1990 through summer 1991, and selected water quality variables were monitored. Mean values for water temperature, dissolved oxygen concentration, pH, settleable solids, total suspended soilds, volatile solids, total phosphorus, soluble reactive phosphate, biochemical oxygen demand, total ammonia nitrogen, nitrite, nitrate, and total Kjeldahl nitrogen were basically the same (P> 0.05) between samples taken from the surface and near the bottom. Concentrations of most water quality variables of catfish ponds were higher than those of receiving streams, and especially it had much higher average concentrations of nitrogen and phosphorus than streams.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.697-704
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• 2022

This study was investigated to evaluate the level of acute TAN (total ammonia nitrogen) and NO₂^--N concentrations at pH levels of 6.0, 7.0 and 8.0 for 96 h in juvenile marbled eel Anguilla marmorata (total length 209.0±22.02 mm and body weight 13.0±5.01 g). The result of the present study showed that the survival rate of juvenile eel at TAN concentrations 0, 100, 200, 300, 400, and 500 ppm at pH 6.0, pH 7.0, and pH 8.0 were 100, 100, 96.7, 74.4, 31.1, and 0%; 100, 82.2, 61.1, 36.7, 0, and 0%; and 98.9, 55.6, 8.9, 0, 0, and 0%, respectively. In addition, the survival rate of juvenile eel at NO₂^--N concentrations 0, 100, 200, 300, 400, and 500 ppm at pH 6.0, pH 7.0, and pH 8.0 were 100, 43.3, 21.7, 0, 0, and 0%; 100, 76.7, 65.0, 43.3, 21.7, and 13.3%; and 100, 100, 100, 88.3, 78.3; and 58.3% respectively. The 96h-LC₅₀ at pH 6.0, 7.0, and 8.0 were 332, 235, and 167 mg/L for TAN, and 188, 296, and 711 mg/L for NO₂^--N, respectively. The acute toxicity of TAN to juvenile eel increased exponentially with increase in pH, whereas the acute toxicity of NO₂^--N to juvenile ell increased with low levels of pH and lengthening of exposure time to NO₂^--N.

• Journal of the Korean Society of Food Culture
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• v.12 no.1
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• pp.63-69
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• 1997

This study was carried out in order to analyzed the changes in nitrogen containing taste compounds of three different types of traditional Korean soy sauce with varing ripening period, and to investigates correlation between sensory characteristics and taste compounds contents via contents assay and sensory evaluation of soy sauce samples. Total nitrogen, ammonia type nitrogen and amino type nitrogen contents showed the highest value in Kyupjang. 17 kinds of free amino acid was detected in Chungjangs and 16 kinds of free amino acid was detected in Kyupjang. Nucleotides and their related compounds detected were hypoxanthin, xanthin, IMP, AMP, Inosine, ADP. Free amino acid and nucleotides and their related compounds contents were highest in Kyupjang. Nitrogen related compounds content of high concentration soy sauce ripened over 150 days increased similarly with Kyupjang. In the sensory evaluation of soy sauce taste, Chungjang samples acquired the highest score in the offensive taste test while Kyupjang marked highest score for sweet taste, nutty taste, taste preference. High concentration soy sauce ripend over 150 days yielded the result similar to that of Kyupjang. Sweet taste showed positive correlation with nitrogen compounds. The materials that showed positive correlation with nutty and traditional soy sauce taste and taste preference were nitrogen compound, IMP, AMP. Except for tryptophan, all free amino acid showed positive correlation with nutty and traditional soy sauce taste. Particulary, taste preference correlated to lysine, aspartic acid and glutamic acid.

• Korean Journal of Poultry Science
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• v.24 no.4
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• pp.179-184
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• 1997

Seven-day-old 40 broiler chicks of both sexes were fed the conventional diet containing 0, 0.3, 6 and 0.9％ Quartz porphyry(QP) and water ad libitum until 28 days of age. The excreta water content and nitrogen balance were measured during the experimental period. At the end of the trial, blood samples were collected to measure ammonia, glucose, triglyceride, and total cholesterol concentrations. In addition, intestinal ammonia concentrations were measured. The excreta moisture contents decreased significantly(P < 0.05) as QP levels increased(r= -0.96). Ammonia contents in the intestine tended to increase as QP levels increased, but the ammonia concentration in the blood was not affected by the QP levels. The blood glucose concentration was not changed but blood triglyceride concentration was lower in the 0.3％ QP treatment than the other groups(P < 0.05), Total cholesterol concentration in the blood tended to increase as QP levels increased. The QP 0.3％ treatment showed somewhat higher positive N balance than the other groups. The results of this experiment indicate that the dietary supplementation of QP could offer some benefits to broiler growers.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.87-95
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• 2020

The worldwide shortage of water resources is a major environmental issue. Using pure water for drinking and domestic purposes is a bigger issue than other environmental issues. Industrialization and Urbanization have even polluted rainwater. In China, when it rains, rainwater is stored on the roof or other sources of storage for daily use resulting in pollution. Several studies have been conducted to treat rainwater. The objective of this study is to evaluate the efficiency of constructed wetlands by using ACF as a medium. So, this study aims to treat rainwater in Wuhan city through a Composite Vertical Flow Constructed Wetlands. First, rainwater was stored in the tank while it flows out of the roof, further it is processed in constructed wetlands. The constructed wetlands is consisted with plants Calamus and Chives, adding ACF (prepared from luffa) has achieved great results in this study. Results show that the pollutants have been removed to a considerable level, there were significant differences in removal rates under different HRT at 6h, 9h and 12h respectively. Therefore, Composite Vertical Flow Constructed Wetlands is recommended for total nitrogen and Ammonia nitrogen and total phosphorus.

• Environmental Engineering Research
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• v.14 no.4
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• pp.238-242
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• 2009

This study investigated the effects of organic loading rates on simultaneous carbon and nitrogen removal in an innovative fixed-film aerobic bioreactor. The fixed-film bioreactor (FFB) was composed of a two-compartment aeration tank, in which a synthetic filamentous carrier was submerged as biofilm support media, and a settling tank which polyvinylidene media (Saran) was used as settling aid for suspended solids. Three different organic loading rates, ranging from 0.92-2.02 kg chemical oxygen demand/$m^3$/day were applied by varying hydraulic retention time (HRT). The total soluble organic carbon removal efficiencies were in the range of 90-97%. The removal efficiency of ammonia was found to be in the range of 70-84%. Total nitrogen removal efficiency was found to be in the range of 40-45%, which indicates that denitrification reactions occurred simultaneously in the attached biofilm on the fibrous media in the aeration tank. The settling performance of suspended solids was significantly improved due to the presence of Saran media in the settling compartment, even for a short HRT. The fixed-film aerobic bioreactor used in this study demonstrated efficient treatment efficiency even at higher organic loading rates and at short HRTs.

• Journal of the Korean Society of Food Culture
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• v.31 no.6
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• pp.643-651
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• 2016

This study was investigated the difference in the quality characteristics of the fermented soybean roasted with different conditions for making chungyukjang. Roasted condition of soybean was decided by pre-test, which was on $140^{\circ}C$ for 21 min, $180^{\circ}C$ 9.5 min, and $220^{\circ}C$ 6 min. Fermented soybean with different roasted condition and conventionally made cheonggukjang were measured for proximate composition, color, pH, amino nitrogen, ammonia nitrogen, free sugar and amino acids. The lightness and yellowness of soybean fermented by conventional method was higher than those of the fermented soybean with roasted soybean. The contents of free sugar of fermented soybean roasted on $220^{\circ}C$ for 6 min (FS220) was the highest among the group and followed by fermented soybean roasted on $180^{\circ}C$ for 9.5 min (FS180), $140^{\circ}C$ 21 min (FS140) and conventional cheonggukjang (FS0). The contents of total free amino acid was highest on fermented soybean roasted on $140^{\circ}C$ for 21 min (FS140) and followed by fermented soybean roasted on $180^{\circ}C$ for 9.5 min (FS180), $220^{\circ}C$ 6 min (FS220) and conventional cheonggukjang (FS0).

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.1
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• pp.24-30
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• 1981

A pot Experiment and a field investigation were carried out in order to obtain some information on the ammonia volatilization and nitrogen absorption by paday rice plants in relation to the potassium application and roots growth. Results obtained were as follows ; 1. Urea application to the polt where potassium was added and rice plant was grown increased the ammonia volatilization at the beginning, but in the latter stage, the volatilization gradually decreased below that of no potassium plot. 2. Total nitrogen absorbed by rice plant, however, was much greater from the potassium added plot than no potassium and pH of the wet soil was lower in the former treatment than in the latter. 3. The application of urea presumably caused greater raise of soil pH and higher ammonia valatilization from the potassium added plot than the no potassium at the beginning, but the active growth of plants and raveneous absorption of N by the plants at the later stage of plant growth resulted in lower ammonia volatilization and lower pH in the potassium added plot than no potassium plot. 4. When the penetration of rice roots was restricted, pH of the wet soil was lower in the plot where potassium added than no potassium, and so was the ammonia volatilization. 5. Under high pH condition of paddy soil, a heavier basal application of potassium chloride or potassium sulfate may reduce the ammonia volatilization particulary in the early growth period of paddy rice when the nutrient absorption by plant is insignificant. However, under an acid normal soil, it may cause ammonia loss through raise of soil pH at the early growth of paddy rice.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.440-447
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• 2009

Domestic ruminant animals are reared in diverse production systems, ranging from extensive systems under semi-arid and tropical conditions with poor feed resources to intensive systems in temperate and cold areas with high quality feed. Nitrogen (N) recycling between the body and gut of ruminants plays a key role in the adaptation to such diverse nutritional conditions. Ammonia and microbial protein produced in the gut and urea synthesized in the liver are major players in N-recycling transactions. In this review, we focus on the physiological factors affecting urea production and recycling. Sheep and buffalo probably have higher abilities to reabsorb urea from the kidney compared with cattle. This affects the degree of urea-N recycling between the body and gut at both low and high N intakes. The synthesis and gut entry of urea also differs between cattle bred for either dairy or beef production. Lactating dairy cows show a higher gut entry of urea compared with growing cattle. The synthesis and recycling of urea dramatically increases after weaning, so that the functional development of the rumen exerts an essential role in N transactions. Furthermore, high ambient temperature increases urea production but reduces urea gut entry. An increase in total urea flux, caused by the return to the ornithine cycle from the gut entry, is considered to serve as a labile N pool in the whole body to permit metabolic plasticity under a variety of physiological, environmental and nutritional conditions.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.214-225
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• 2011

The objectives of the study were to evaluate seasonal patterns of epilimnetic water quality, and determine interannual eutrophication patterns at the dam site of Yong-dam Reservoir using long-term data during 2002~2009. Ionic dilutions, based on specific conductivity, occurred in the summer period in response to the intense monsoon rain and inflow, and suspended solid analysis indicated that the reservoir was clear except for the monsoon. Seasonality of nitrogen contents varied depending on the types of nitrogen and responded to ionic dilution; Ammonia-nitrogen ($NH_4$-N) peaked at dry season but nitrate-nitrogen ($NO_3$-N) peaked in the monsoon when the ionic dilution occurred. The maxima of $NO_3$-N seemed to be related with external summer N-loading from the watershed and active nitrogen fixation of bluregreens in the summer. $NO_3$-N was major determinant (>50%) of the total nitrogen pool and relative proportion of $NH_4$-N was minor. Long-term annual $NO_3$-N and TDN showed continuous increasing trends from 2004 to 2009, whereas TP and TDP showed decreasing trends along with chlorophyll-a (CHL) values. Empirical model analysis of log-transformed nutrients and N : P ratios on the CHL showed that the reservoir CHL had a stronger linear function with TP ($R^2$=0.89, p<0.001) than TN ($R^2$=0.35, p=0.120). Overall results suggest that eutrophication progress, based on TP and CHL, is slow down over the study period and this was mainly due to reduced phosphorns, which is considered as primary nutrient by the empirical model.