• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.248-254
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• 2016

Efficacious wastewater treatment is essential for increasing sewage sludge volume and implementing strict environmental regulations. The operation cost of sludge treatment amounts up to 50% of the total costs for wastewater treatment plants, therefore, an economical sludge destruction method is crucially needed. Amid several destruction methods, wet air oxidation (WAO) can efficiently treat wastewater containing organic pollutants. It can be used not only for sludge destruction but also for useful by-product production. Volatile fatty acids (VFAs), one of many byproducts, is considered to be an important precursor of biofuel and chemical materials. Its high reaction condition has instituted the study of gravity pressure reactor (GPR) for an economical process of WAO to reduce operation cost. Simulation of subcritical condition was conducted using Aspen Plus with predictive Soave-Redlich-Kwong (PSRK) equation of state. Conjointly, simulation analysis for GPR depth, oxidizer type, sludge flow rate and oxidizer injection position was carried out. At GPR depth of 1000m and flow rate of 2 ton/h, the conversion and yield of VFAs were 92.02% and 0.17g/g, respectively.

• Korean Journal of Poultry Science
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• v.6 no.2
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• pp.83-90
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• 1979

In order to evaluate the effect of lipids on the utilization of the energy and Protein of the diet, the isocaloric and isoprotein diets added with mutton fat, tallow, and lecithin at the levels of two percent and five percent were prepared. The growth of chicken and the feed efficiency were observed on hatched chicken which were fed a commercial diet for the first week, with starters for the next four weeks, and with finisher diets for the last three weeks respectively during the eight weeks of the experiment. Growth rate, feed efficiency, and average body weight gain per day were similar among the chicken fed diets containing various lipids or at the levels of two percent and five percent. The metabolizable energy of the diets was found to be from 2.713kcal to 3.059kcal per gram, and the metabolizability of the gross energy was from 62 percent to 70 percent. Also the metabolizability of basal diet was higher as compared with the diets containing lipids. And the lower energy utilization was found in the broilers fed diets containing five percent lipids than those of two percent, showing not significant difference between them. Daily metabolizable energy of three week old birds ranged from 132kca1 to 168kcal which resulted in also a tendency of lower values in the five percent diets. And daily retained nitrogen of birds ranged from 0.631 gr to 0.738 gr, which showed an increasing tendency on the birds fed five percent mutton fat and tallow in comparison with those of two percent. But the lecithin brought about a reverse tendency. The digestibility of crude fats was found to be from 48 percent to 76 percent, but not significant difference among diets plus lipids or at the levels of two percent and five percent. The birds fed five percent mutton fat and tallow showed a tendency of lower digestibility as. compared with those fed two percent, but the similar results were found between two percent and five percent lecithin fed to the birds. Then, it was tentatively concluded that the effect of the mutton fat on the energy and protein utilization was similar to tallow but resulted different tendency with lecithin.

• Progress in Medical Physics
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• v.10 no.1
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• pp.17-22
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• 1999

INJ-I, INJ-E, PFN, BMI, and PRF were selected among the various factors which constitute a digital linear accelerator to find effects on the dose distribution by changing current and voltage within the permitted scale which Mevatron automatically maintained. We measured the absorbed dose using an ion chamber, analyzed the waveform of beam output using an oscilloscope, and measured symmetry and flatness using a dosimetry system. An RFA plus (Scanditronix, Sweden) device was used as a dosimetry system. Then an 0.6cc ion chamber (PR06C, USA), an electrometer (Capintec192, USA), and an oscilloscope (Tektronix, USA) were employed to measure the changes on the dose distribution characteristics by changing the beam-tuning parameters. When the currents and the voltages of INJ-I, INJ-E, PFN, BMI, and PRF were modified, we were able to see the notable change on the dose rate by examining the change of the output pulse using the oscilloscope and by measuring them using the ion chamber. However, the results of energy and flatness graph from RF A plus were almost identical. The factors had fine differences: INJ-I, INJ-E, PFN, BMI, and PRF had 0.01∼0.02% differences in D10/D20, 0.1∼0.2 % differences in symmetry, and 0.1∼0.4% differences in flatness. Since Mevatron controlled itself automatically to keep the reference value of the factor, it was not able to see large differences in the dose distribution. There were fine differences on the dose rate distribution when the voltage and the currents of the digitized factors were modified Nonetheless, a basic operational management information was achieved.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.894-899
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• 2001

Intakes and excretions of zinc and copper were determined for 8 female adolescents (aged 16.4$\pm$0.5 y; body mass index 20.4$\pm$1.3kg/$m^2$; body fat 33.3$\pm$2.5%; bone mineral density of lumbar spine in L2-L4; 0.96$\pm$0.08g/$\textrm{cm}^2$) when they consumed diets basal and high in calcium for 6 days each. All subjects consumed a basal Ca diet containing 800 mg, Korean RDA level of the subjects, and a high Ca diet containing 1200mg, RDA plus 2 SDs of calcium intake. The diets provided 58% of energy intake as carbohydrate, 25% as fat, and 17% as protein. Food, urine and fecal samples were collected during the last 3 days of each feeding period and were assayed. Mean daily intakes on the basal and high calcium diets, respectively, were 6.57 and 6.37 mg for zinc and 910 and 812 $\mu\textrm{g}$for copper. Fecal excretion of copper and zinc in relation to intake was significantly greater on the high calcium than on the basal calcium diet. Hence, apparent absorption rate was significantly lowered from 98.7% on the basal calcium diet to 97.9% on the high calcium diet for zinc from 66.3% to 56.4% for copper, respectively. Urinary loss of copper was not detectable but that of zinc was 0.38mg on the basal diet and 0.47mg on the high calcium diet. Copper retention was 899$\pm$105$\mu\textrm{g}$/day on the basal calcium diet and 792$\pm$20.8$\mu\textrm{g}$/day on the high calcium diet, and zinc retention was 3.95$\pm$0.91mg/day and 3.11$\pm$0.89mg/day. Thus, copper and zinc retention was significantly decreased on the high calcium diet (p<0.05). Summarizing the results, apparent absorption and retention of zinc and copper were significantly decreased by calcium supplementation. Therefore, it is suggested that interactions among minerals should be considered in determining RDA.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.8
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• pp.1164-1172
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• 2011

Two experiments were conducted to evaluate the efficacy of Trichoderma reesei derived phytase for pigs fed diets with fixed calcium to total phosphorus ratios (1.5:1). In Exp. 1, 280 weaned pigs (initial BW of $10.32{\pm}1.94$ kg) were allocated to one of five dietary treatments on the basis of weight and gender in a randomized complete block design. Treatments were the low phosphorus (0.6% Ca, 0.4% total P and 0.23% available P) diets supplemented with 0, 250, 1,000, or 2,000 FTU phytase/kg of diet and a positive control diet (PC; 0.85% Ca, 0.58% total P and 0.37% available P). The treatments were applied to seven pens with eight pigs per pen, half male and half female. In Exp. 2, six barrows fitted with ileal T-cannula (initial BW = $35.1{\pm}1.6$ kg) were assigned to three dietary treatments with a double $3{\times}3$ Latin square design. The dietary treatments were the low-phosphorus diet (0.53% Ca, 0.34% total P and 0.14% available P), the low phosphorus diet plus 1,000 FTU phytase/kg and a positive control diet (0.77% Ca, 0.50% total P and 0.30% available P). In Exp. 1, there were linear increases (p<0.01) in weight gain, phosphorus absorption, bone strength, calcium and phosphorus content of fat-free dried bone and plasma phosphorus concentrations with increasing dose rate of phytase. The performance of pigs fed the diets with 250, 1,000, or 2,000 FTU of phytase/kg did not differ from pigs fed the PC diet. Pigs fed diets with 1,000 or 2,000 FTU of phytase/kg did not differ from pigs fed the PC diet in bone characteristics. The apparent digestibility of dry matter, crude protein, ash and energy was not affected by dietary treatment. However, pigs fed the PC diet excreted more fecal phosphorus (g/d, p<0.01) and fecal phosphorus per BW gain (g/kg) than pigs fed the diets with phytase. Phytase linearly decreased (p<0.01) fecal phosphorus excreted per BW gain (g/kg), plasma calcium concentration as well as plasma and bone alkaline phosphatase activity. In Exp. 2, phytase supplementation in the low-P diet increased (p<0.05) the apparent ileal digestibility (AID) of Ca, P, leucine, lysine, phenylalanine, alanine and cysteine, tended to AID of crude protein, isoleucine, threonine, asparagine and serine. In conclusion, the novel phytase originated from Trichoderma reesei is effective in releasing Ca, P, and amino acids from corn soy based diet for pigs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.9
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• pp.1208-1214
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• 2011

Caffeine, a psychoactive stimulant, has been implicated in the modulation of learning and memory functions due to its action as a non-selective adenosine receptors antagonist. On the contrary, some side effects of caffeine have been reported, such as an increased energy loss and metabolic rate, decrease DNA synthesis in the spleen, and increased oxidative damage to exerted on LDL particles. Therefore, the aim of this study was to develop a safe stimulant from natural plants mixture (Aralia elata, Acori graminei Rhizoma, Chrysanthemum, Dandleion, Guarana, Shepherd's purse) that can be used as a substitute for caffeine. Thirty SD rats were divided into three groups; control group, caffeine group (15.0 mg/kg, i.p.), and natural plants mixture group (NP, 1 mL/kg, p.o.). The effect of NP extract on stimulant activity was evaluated with open-field test (OFT) and plus maze test for measurement of behavioral profiles. Plasma lipid profiles, lipid peroxidation in LDL (conjugated dienes), total antioxidant capacity (TRAP) and DNA damage in white blood, liver, and brain cells were measured. In the OFT, immobility time was increased significantly by acute (once) and chronic (3 weeks) supplementation of NP and showed a similar effect to caffeine treatment. Three weeks of caffeine treatment caused plasma lipid peroxidation and DNA damage in liver cells, whereas there were no changes in the NP group. NP group showed a higher plasma HDL cholesterol concentration compared to the caffeine group. The results indicate that the natural plants mixture had a stimulant effect without inducing oxidative stress.