• Journal of Korean Society of Environmental Engineers
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• v.28 no.9
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• pp.911-916
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• 2006

The influence of substrate concentration and hydraulic retention time(HRT) on the hydrogen production by anaerobic microflora was investigated by conducting three series of continuous experiments the individual influences of substrate concentration and HRT. In series I, substrate concentration was increased from 3 to 27 g-glucose/L keeping HRT at 8 hr. Series II and III carried out same condition with series I at HRT of 16 hr and 24 hr, respectively. The effects of HRT and substrate concentration on the hydrogen production yield were analyzed by quadratic model. The maximum hydrogen production yield of 2.05 mol $H_2/mol$ glucose was found at the HRT of 9.6 hr and the substrate concentration of 15.4 g/L. The relationship between HRT and substrate concentration on hydrogen production yield as displayed a saddle shape in the response surface plot. Optimum HRT and substrate concentration are observed at in the range of 5 and 14 hr, at between 13 and 17 g/L, respectively, for the hydrogen production yield being 2 mol $H_2/mol$ glucose. The concentrations of organic acids increased with the increase of the amount of glucose consumption. Acetic acid and butyric acid were the main by-products from the glucose degradation.

• Korean Journal of Poultry Science
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• v.27 no.1
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• pp.43-50
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• 2000

Two experiments were conducted to investigate the effect of dietary supplemental lincomycin at different food waste supplements on performance of broiler chicks. Diets were based corn, soybean meal and contained 3,078, 3,089 ㎉/kg ME, 21% CP for the first three weeks and 3,116 ㎉/kg and 19% CP for the rest two weeks. Three levels of lincomycin(LM; 0, 2.2, 4.4mg/kg) and food waste (FW;0, 5, 10%) were differently used for both experiments. Weight gain, feed intake, feed conversion ratio were weekly measured for five weeks. Blood components, liver and abdominal fat were sampled at the end of experiments. In experiment, 1 weight gain of birds fed 4.4mg/kg LM was significantly higher than that of no LM treatments (p<0.05). It was tended to decrease in 10% food waste treatment compared to that of control but was not significantly different. FCR of chocks fed LM supplement tended to improve as dietary LM level increased. It was not superior in 10% food waste treatment to that of control, but tended to improve compared to that of other treatments. Weight gain and FCR of birds fed 2.2mg/kg LM without food waste tended to improve compared to those of other treatments, but were not significantly different. Liver to body weight ratio birds fed LM supplements regardless of FW decreased significantly compared to that of control (p<0.05), but was not consistency in FW treatments. There was no significance in blood components except blood protein. In experiment 2, weight gain of chicks fed no FW showed quadratic, but increased as dietary supplemental LM increased. Birds fed 5% FW was not superior weight gain to that of other FW treatments. It also decreased in no LM treatment with 10% FW compared to that of control. However, the birds fed 4.4 mg/kg LM with 10% FW exhibited significantly higher weight gain the trend of weight gain. It tended to increase up to 10% FW combined with 4.4 mg/kg LM, but was not significantly different. Liver to body weight ratio of chicks fed LM was significantly decreased more than the control(p<0.05).The results of these experiments indicated that chicks fed 10% FW with 4.4 mg/kg LM supplements maximized growth rate of all treatments, but was not improve FCR in both experiments.

• The Korean Journal of Rheology
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• v.10 no.4
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• pp.195-201
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• 1998

We have studied the rheological and electrical properties of two types of electrorheological (ER) fluids based on semi-conductive polymers (poly(p-phenylene) and polyaniline). These semi-conductive polymer-based suspensions showed a dramatic increase in viscosity on the application of the static electric field due to the large value of conductivity ratio between particle and medium. The dynamic yield stresses of these ER suspensions exhibited a quadratic dependence on electric field strength at low electric fields and a linear one for high fields. They showed a maximum and then decreased with increasing bulk conductivity of particles. These yield stress behaviors under the static electric field were found to be closely related to the dielectric properties, which is in accord with Maxwell-Wagner interfacial polarization induced by the conductivity effects. In order to achieve better understanding of interfacial polarization effect on ER response and to improve the stability of ER suspension, different kinds of surfactants were employed for controlling the ER activity as well as for enhancing the colloidal stability of suspensions.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.9
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• pp.1345-1353
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• 2015

This study was conducted to investigate the influence of dietary rapeseed meal (RSM) on growth performance, blood profiles, nutrient digestibility and economic benefit of growing-finishing pigs. A total of 120 growing pigs ($[Yorkshire{\times}Landrace]{\times}Duroc$) with an initial body weight (BW) $29.94{\pm}0.06kg$ were used in this experiment. Pigs were randomly allotted into 1 of 5 treatments in a randomized complete block design and 6 replicates with 4 pigs per pen. Treatments were divided by dietary RSM supplementation levels (0%, 3%, 6%, 9%, or 12%) in growing-finishing diets. A linear decrease (p<0.05) of BW and average daily gain (ADG) were observed at 13th wk of finishing and overall periods of pigs. Additionally, gain-to-feed ratio (G/F) tended to decrease by dietary RSM supplementation in growing-finishing diets (linear, p = 0.07 and quadratic, p = 0.08). Concentrations of serum triiodothyronine and thyroxine were not influenced by dietary RSM treatments whereas thyroid gland and liver weight were increased at 13th wk of finishing period (linear, p<0.05; p<0.01) by increasing dietary RSM supplementation level. In blood profiles, serum total cholesterol and low density lipoprotein cholesterol concentrations were not differed by dietary treatments at 13th wk of finishing period whereas concentration of serum high density lipoprotein cholesterol was affected by the supplementation level of RSM, resulting in a linear RSM level responses (p<0.05). Serum blood urea nitrogen concentration tended to decrease (linear, p = 0.07; p = 0.08) at 6th wk of growing and 13th wk of finishing periods and digestibility of dry matter tended to decrease by dietary RSM (linear, p = 0.09). Crude protein, crude fat and nitrogen retention, whereas, were not affected by dietary RSM supplementation level. In the economic analysis, feed cost per weight gain was numerically decreased when RSM was provided up to 9%. Consequently, RSM could be supplemented to growing-finishing diets up to 9% ($3.07{\mu}mol/g\;Gls$) without detrimental effects on growth performance of growing-finishing pigs.

• Journal of Biosystems Engineering
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• v.9 no.1
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• pp.22-33
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• 1984

Husk separator is an indispensable equipment in rice milling plants. However, any basic research on the designing and operating criteria of the husk separator have rarely been conducted in Korea. According to the survey results reported recently, grain loss occurs in the process of rice husk separation at custom rice milling plants in Korea and the performance of husk separator has also not been identified. With this regard this study was conducted with a typical commercial husk separator to investigate the effect of the operational factors such as feed rate, blower speed and opening ratio on the velocity distribution in the air duct and the performance of the separator. The results are summerized as follows: 1. The average wind velocity in the primary air duct increased linearly with the blower rpm and the size of air inlet port in both cases of double type and single type operations. 2. The coefficient of variation in the horizontal wind velocities in the primary air duct was the minimum when the opening ratio was 0.22 ($0.052m^2$ of air inlet port) in both cases of single type and double type operations regardless of the blower speeds used in this test. The average wind velocity at the upper part of air duct was greater by 2-5 m/s than the velocity at the bottom part in double type operation. In case of single type operation, however, the average velocity in the middle part was greater than the upper or bottom part when the opening ratio was greater than 0.74. 3. The relationship between the overall effectiveness of separation(Ed for double type and Es for single type) and the average wind velocity (Va) in the primary air duct was expressed in the following quadratic functions. $$Ed=-190.84+106.18Va-10.052Va^2$$ ($r^2$ = 0.97782) $$Es=-223.76+106.23Va-9.1935Va^2$$ ($r^2$ = 0.97029) The average wind velocity required to obtain the overall effectiveness of separation more than 80% ranged from 4.04 m/sec to 5.84 m/sec in case of double type operation, and from 4.70 m/sec to 6.20 m/sec in case of single type. 4. An optimum wind velocity can be obtained with an increase in the blower speed or the size of air inlet port as presented in Figure 8. There was a tendency that the faster the blower speed, the narrower the control range of the air inlet port. 5. The feed rates (1850kg/hr and 2100kg/hr) adopted in this experiment did not bring about a significant difference in both the overall effectiveness of separation and the power consumption. 6. The energy consumption increased cubically with the blower speed but linearly with the size of the air inlet port. On the basis of the results described in items 1, 3, and 6, it would be more economic to adjust the size of the air inlet port larger with a relatively low blower speed than to adjust the size smaller with a relatively high speed.

• Journal of Animal Science and Technology
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• v.54 no.5
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• pp.349-354
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• 2012

In this experiment, two inclusion levels (15 and 30% of diets, as-fed basis) of brown rice (BR) were tested against a control diet with 0% BR (51% wheat flour of diet). Six female Miniature Poodles (8~9 months age, initial mean body weight of 3.5 kg) were assigned to treatments in replicated $3{\times}3$ Latin square design. Total tract digestibilities of DM, OM, CP, acid hydrolyzed fat and gross energy increased linearly (P<0.05), and observed digestible energy and metabolizable energy values also increased linearly (P<0.001 and P=0.007, respectively) with increasing BR inclusion levels. Wet and dry fecal output decreased linearly (P=0.001) with increasing BR inclusion levels in the diets. Linear (P<0.05) effects was observed in fecal score for dogs fed BR and fecal ammonia concentration increased linearly (P<0.05) in response to increasing BR inclusion level. It seems that the increase in fecal ammonia concentration may be partially related to the decrease in short-chain fatty acid concentration (P<0.01). This study clearly demonstrates that BR improves nutrients digestibility and fecal characteristics of dog.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.371-377
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• 2009

The objectives of the present study were to investigate the effects of different dietary ratios of whole-crop corn silage and alfalfa hay on nitrogen (N) digestion, duodenal flow and metabolism across the portal-drained viscera (PDV) of growing beef steers, and to elucidate their relationships. Four steers (236${\pm}$7 kg BW) fitted with duodenal cannulae and chronic indwelling catheters into the portal and mesenteric veins and abdominal aorta were used in a 4${\times}$4 Latin square design. Animals were fed (at 12-h intervals) the 4 diets consisting of whole-crop corn silage (C) and alfalfa hay (A) in 80:20 (C8A2), 60:40 (C6A4), 40:60 (C4A6) and 20:80 (C2A8) ratios of which dietary crude protein (CP) was 10.5, 12.0, 13.5 and 15.0% of dry matter (DM), respectively. Feeding level was restricted to 95% of ad libitum intake to measure N digestion, blood flow and net flux of N across the PDV. Digestibility of DM and neutral detergent fiber and digestible energy intake linearly increased as the ratio of alfalfa hay increased. The N intake, duodenal flow and intestinal disappearance increased linearly with increasing alfalfa hay. Arterial and portal concentrations of ${\alpha}$-amino N showed a quadratic response to increasing levels of alfalfa hay and were the highest in steers fed the C6A4 diet. The net PDV release of ${\alpha}$-amino N and ammonia N increased linearly with increasing alfalfa hay, but urea N uptake by PDV did not differ among diets. As a percentage of apparently digested N in the total gut, net PDV release of ${\alpha}$-amino N linearly decreased from 66 to 48% with increasing alfalfa hay. Conversely, net PDV recovery of ${\alpha}$-amino N to intestinal N disappearance varied with increasing alfalfa hay accounting for 49, 50, 58 and 61% on C8A2, C6A4, C4A6 and C2A8 diets, respectively. Net PDV uptake of urea N, relative to apparently digested N, linearly decreased from 81 to 25% as alfalfa hay increased from 20 to 80% of DM intake. Considering PDV uptake of urea N, microbial efficiency and conversion of total tract digested N to PDV ${\alpha}$-amino N net supply, a diet consisting of 80% whole-crop corn silage and 20% alfalfa hay (10.5% CP) was the best, while considering the quantities of intestinal N disappearance and ${\alpha}$-amino N absorption, a diet of 20% whole-crop corn silage and 80% alfalfa hay (15% CP) would be preferred. The proportion of ${\alpha}$-amino N recovered by PDV relative to the intestinal N disappearance may vary with energy intake level of mixed forage diets.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.97-104
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• 2003

Hydrogen fermentation of food waste and sewage sludge was performed in serum bottles under various volatile solids(VS) concentrations(0.5~5.0%) and mixing ratios of two substrates(0:100-100:0, VS basis). Full quadratic equations, optimal conditions, and 90% acceptable conditions for hydrogen production potential and rate were obtained using cumulative methane production data and response surface methodology. The specific hydrogen production potential of food waste was higher than that of sewage sludge. However, hydrogen production potential increased as sewage sludge composition increased up to 13~19% at all the VS concentrations. The maximum specific hydrogen production potential of 122.9 mL/g $carbohydrate_{added}-COD$ was found at the waste composition of 87:13(food waste:sewage sludge) and the VS concentration of 3.0%. The relationship between carbohydrate concentration, protein concentration, and hydrogen production potential indicated that enriched protein by adding sewage sludge might enhance hydrogen production potential. The maximum specific hydrogen production rate was 111.2 mL $H_2/g$ VSS/h. Food waste and sewage sludge were, therefore, considered as a suitable main substrate and a useful auxiliary substrate, respectively, for hydrogen production.

• Korean Journal of Agricultural Science
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• v.11 no.2
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• pp.284-294
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• 1984

Effects of orifice diameter, operating angle and swirl chamber distance were examined to study a reasonable distribution pattern on the maximum available travel distance in the triple nozzle system. The results of the study were as follows; 1. Discharge rate was increased with increase of orifice diameter, and a quadratic line for the 1st nozzle and linear lines for the 2nd or the 3rd nozzle. 2. The operating angle of $15^{\circ}$ had showed the maximum available travel distance, and 17m in orifice diameter of 3.0mm and operating pressure of $24.5{\times}10^5pa$ ($25Kg/cm^2$). 3. Nozzle setting methods (reference Table 6.) for improvement of uniformity of deposit distribution were varied depending on the size of orifice diameter of the 1st nozzle, nevertheless coefficients of uniformity were improved about 6 percents. 4. Adjustment of the swirl chamber distance of the 2nd nozzle could improve the minimum area of about 6m from the triple nozzle.

• Korean Journal of Poultry Science
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• v.30 no.1
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• pp.61-66
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• 2003

This study was conducted to investigate the effects of dietary germanium biotite supplementation on egg quality and fecal noxious gas content in laying hens. One hundred and forty-four 40-wk-old, ISA Brown layers were used in this experiment. Dietary treatments were 1) CON(control diet), 2) GB0.5(control diet + 0.5% germanium biotite), 3) GB1.0 (control diet + 1.0% germanium biotite) and 4) GB1.5(control diet + 1.5% germanium biotite). Hen-day egg Production and egg shell breaking strength were not influenced by germanium biotite supplementation. However, egg weight decrease as the level of germanium biotite supplementation increased in the diets increased(Cubic effect, p<0.02). Eggshell thickness, yolk color and yolk index were not influenced by garmanium biotite supplementation. Serum triglyceride concentration as dietary germanium biotite increased (linear effect P<0.02; quadratic effect, p<0.05). Dietary supplementation of germanium biotite reduced fecal NH$_3$-N concentration (P<0.01), propionic acid(P<0.01), butyric acid( P<0.05) and acetic aicd(P<0.01) concentrations in the feces. In conclusion, the results of this experiment indicated that dietary germanium biotite supplementation did not affect egg shell quality, but reduced fecal NH$_3$-N concentration.