• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.2
• /
• pp.39-45
• /
• 2005

The aim of this research is to predict the thickness and loading noise of the round-tip shaped Hartzell propeller currently used in the general aviation aircraft. Before implementing the noise analysis, the pressure distribution on the propeller was obtained by using the free wake panel method and unsteady Bernoulli's equation. The noise signal at observer position can be obtained by using the FW-H equation. The noise prediction results for the propeller indicates that the thickness noise has s symmetric directivity pattern with respect to the tip path plane, while the noise due to loading shows higher noise directivity toward downstream than the upstream direction from the rotor plane. The loading noise is dominant rather than the thickness noise in normal operating condition.

• Journal of Animal Science and Technology
• /
• v.47 no.4
• /
• pp.513-524
• /
• 2005

This study was conducted to introduce recycling procedures of food waste(FW) as feed according to the dehydration, semi-dehydration fermentation and liquid fermentation methods through the on-site survey of companies related, to trace physico-chemical components and nutritional losses depending upon the processing stage for each method and finally to suggest more desirable methodology for the efficient utilization of FW as animal feed. For the dehydration method, dewatering of FW alone reduced(P<0.05) moisture(approximately 10%) and ether extract contents and increased(P<0.05) fiber contents. Dewatering and subsequent dehydration of FW decreased(P<0.05) contents of ether extract, limiting amino acids such as lysine, methionine and histidine, pepsin digestibility of protein by half, and NaCl content by 40%, increased(P<0.05) contents of fiber, crude ash, Ca and P, and did not alter(P>0.05) pH. The semi-dehydration fermentation method of FW did not affect(P>0.05) the chemical components, pepsin digestibility of protein, pH and NaCl content. For the liquid fermentation method, pasteurization and fermentation of FW decreased(P<0.05) contents of dry matter, ether extract, crude fiber, lysine and NaCl; however, it did not affect(P>0.05) other chemical components, pepsin digestibility of protein and pH. Among the processing methods, nutrient losses were highest for the dehydration method(25% of metabolizable energy loss, 12% of organic matter loss) and little for the semi-dehydration and liquid fermentation methods. The on-site survey of companies related revealed that the existence of foreign materials in FW products were problematic for all the three companies surveyed, thus it was necessary to develop a more efficient screener. Before feeding FW-containing diets to pigs, high quality of protein and energy feedstuffs needed to be fortified for the dehydration method. For the semi-dehydration fermentation method, the scientific diet formulation technology was required at the initial mixing stage. For the liquid fermentation method, possibly most energetic and proteinaceous feeds needed to be supplemented for the normal animal growth.

• Korean Journal of Poultry Science
• /
• v.32 no.4
• /
• pp.275-279
• /
• 2005

This study investigated the effect of dried food-waste diets (FW) fermented by Aspergillus oryzae (AEW), on egg Production and egg qualify in laying hens. One hundred sixty eight laying hens, 50 week old, ISA-Brown wtrain were randomly distributed into 7 treatments with 3 relpicates of 8 birds per replicate and fed with standards laying hen diet replaced with FW and AFW at die=rent level Basal Diet, 25, 10, $75\%$, respectively. There was a significant decrease in feed intake for FW $50\%$ diet and egg Production was statistically lower in all W diet treatments(p<0.05). Water consumption was increased as the replacement increased. Egg weight, egg shell thickness and strength were similar among treatments. However, egg yolk color and Haugh unit showed distinct differences when W were added to their diets(p<0.05). No difference was observed in egg yolk cholesterol. It seems that FW diet could decrease the egg Production, but would be able to improve egg Quality. From this results, AO seemed applicable to laying hen diet as supplements.

• Journal of Environmental Health Sciences
• /
• v.23 no.4
• /
• pp.121-126
• /
• 1997

Peroxidase as one of the organic enzyme catalyst is useful for the oxidation treatment of various aromatic compounds such as phenols. The peroxidase content of Oenanthe javanica was 24.85 unit/g-fw in leaf, 5.74 unit/g-fw in stem, and 34.69 unit/g-fw in root respectively. The crude peroxidase extracted from Oenanthe javanka can be kept under low temperature (-70$\circ$C) condition for 6 months with the maximum 1% activity reduction. The optimum conditions of removal for 100 ppm phenol was pH 6, hydrogen peroxide 3.5 mM, peroxidase activity 8 unit/ml, temperature 20$\circ$C respectively. In the wide range of concentration from 50 ppm to 750 ppm phenol reveals average 54% removal rate under the same peroxidase activity (8 unit/ml) and different amount of hydrogen peroxide proportional to phenol concentration. Especially at the concentration of 100 ppm the maximum phenol removal rate was 72%.

• Korean Journal of Poultry Science
• /
• v.32 no.2
• /
• pp.89-96
• /
• 2005

This studies were conducted to investigated the feeding effects of extruded broiler manure(BMERF) mixture and swine manure(SFERF) mixture on laying performance and egg qualify of laying hens. As a experimental feed, broiler manure, corn and tapioca were mixed in 50, 30 and $20\%$ to use for treated extrusion feed(BMERF, Exp. 1) and food waste(FW), swine manure and com were also mixed in 40, 40 and $20\%$ to use it(SFERF, Exp. 2) and implemented during 12 weeks, four replication and 30 chick of each treatment. The nutritional ingredients(protein, energy and calcium contents) of food waste, broiler manure and swine manure had been significantly improved(p<0.05) when handling extrusion. In the Exp. 1, the feed intake was much higher BMERF $40\%$ and BMERF $20\%$ than control and BMERF $10\%(p<0.05)$, the egg production of control, BMERF $10\%$ and BMERF $20\%$ were not significantly difference(p>0.05), but BMERF $40\%$ was significantly lower(p<0.05). The feed efficiency of control and BMERF $10\%$ were not significantly difference(p>0.05), but BMERF $20\%$ and BMERF $40\%$ were significantly lower(p<0.05). York color, White height and Haugh unit did not affected by BMERF additive. In the Exp. 2, the feed intake of control, FW $20\%$, SFERF $10\%$ and SFERF $20\%$ were not significantly difference(p<0.05), but FW $40\%$ and SFERF $40\%$ were significantly higher(p<0.05). The egg production of SFERF $10\%$ and SFERF $20\%$ were not significantly difference(p>0.05) with control, but FW $20\%$, FW $40\%$ and SFERF $40\%$ were significantly lower(p<0.05). The feed efficiency was similar tendency to the egg production, however, the egg weight, york color, white height and haugh unit were not significantly difference among each treatments(p>0.05).

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.6
• /
• pp.843-851
• /
• 2003

An experiment was conducted to investigate the effects of pre-wilting Bana grass (Pennisetum purpureum x P. americanum) herbage under sunny conditions for 0, 6, 18, 24, 32 and 48 h and ensiling it with maize meal. Four levels of maize meal(viz., 0, 5, 10 and 15% on fresh weight (Fw) basis) were tested. The experiment had a split-plot design. Wilting increased the concentration of water soluble carbohydrates (WSC) significantly (p<0.001) on a Fw basis, although there were no significant changes on DM basis. Unwilted grass contained $36.1g{\cdot}WSC{\cdot}kg^{-1}{\cdot}Fw$ ($127.6g{\cdot}kg^{-1}{\cdot}DM$) and this increased to $64.1g{\cdot}WSC{\cdot}kg^{-1}{\cdot}Fw$ ($116.7g{\cdot}kg^{-1}{\cdot}DM$) after 48 h of pre-wilting. Wilting also increased the DM content of herbage significantly (p>0.001) from 250 to $620g{\cdot}kg^{-1}$, between 0 and 48 h respectively. The concentration of fermentation end-products decreased (except butyric acid) and pH increased when the period of wilting increased, indicating that fermentation was restricted. In particular, lactic acid content declined from 50.8 to $26.2g{\cdot}kg^{-1}{\cdot}DM$ (p<0.01) and the residual WSC contents of silage increased from 2.7 with fresh herbage to $18.1g{\cdot}kg^{-1}{\cdot}DM$ with 48 h of wilting (p<0.001). Rapid wilting for 24 h, to a DM of $450g{\cdot}kg^{-1}$ was optimum since important increases in pH, residual WSC and DMD occurred at this level of wilting. Acetic acid, butyric acid and ammoniacal-N contents were lowest with 24 h of wilting. There were no significant interactions between length of wilting and the incorporation of maize meal. Wilting had a greater influence on fermentation than the incorporation of maize meal. Addition of maize meal facilitated fermentation by increasing forage DM content and reducing effluent production. In addition, the maize meal increased DMD. It was concluded that maize meal should generally be incorporated at a level of 5% on fresh weight basis.

• Korean Journal of Environmental Agriculture
• /
• v.42 no.2
• /
• pp.159-167
• /
• 2023

Food waste (FW) emissions in South Korea amounted to 4.77 million tons in 2021, and continue to increase. Various technologies have been developed to treat FW, with recent research focusing on biochar production through pyrolysis to reduce FW. However, the agricultural application of food waste-biochar (FWBC) is limited by the salt accumulated during pyrolysis. This study investigated salt removal from and the kinetic characteristics of FWBC, and subsequently evaluated its agricultural applications. FW was pyrolyzed at 350℃ for 4 h, and subsequently washed for 0.1, 0.25, 0.5, 0.75, 1, 5, 15, and 30 min to remove salt. FWBC had a salt concentration of 5.75%, which was effectively removed through washing. The salt concentration decreased rapidly at the beginning (1 min) and then slowly decreased, unlike in FW, in which the salt decreased continuously and slowly. The salt removal speed constant (K) was 1.5586 (Stage 1, FWBC) > 0.0445 (Stage 2, FWBC) > 0.0026 (FW). In a lettuce cultivation experiment, higher biomass was achieved using washed FWBC than when using unwashed FWBC and FW, and soil properties were improved. Overall, these findings suggest that although FW reduction using pyrolysis causes a salt accumulation problem, the salt can be effectively removed through washing. The use of washed FWBC can enhance plant growth and soil properties.

• Korean Journal of Poultry Science
• /
• v.32 no.4
• /
• pp.291-300
• /
• 2005

Two experiments were carried out to assess the appropriate incubation conditions namely; duration, moisture content and the ideal microbial inoculant for fermented dried food waste(EW) offered to broilers. The nutrient utilization of birds fed the FW diets at varying dietary inclusion rates was also compared with a control diet. In Experiment 1, different moisture contents(MC) of 30, 40, 50 and $60\%$ respectively were predetermined to establish the ideal duration of incubation and the microbial inoculant. A 1mL Aspergillus oryzae(AO) $(1.33\times10^5\;CFU/mL)$ was used as the seed inoculant in FW. This results indicated that the ideal MC for incubation was $40\~50\%$ while the normal incubation time was > 72 hours. Consequently, AO seeds at 0.25, 0.50, 0.75 and 1.00mL were inoculated in FW to determine its effect on AO count. The comparative AO count of FW incubated for 12 and 96 hours, respectively showed no significant differences among varying inoculant dosage rates. The FW inoculated with lower AO seeds at 0.10, 0.05 and 0.01mL were likewise incubated for 72 and 96 hours, respectively and no changes in AO count was detected(p<0.05). The above findings indicated that the incubation requirements for FW should be $%40\~50\%$ for 72 hours with an AO seed incoulant dosage rate of 0.10mL. Consequently, in Experiment II, after determining the appropriate processing condition for the FW, 20 five-week old male Hubbard strain were used in a digestibility experiment. The birds were divided into 4 groups with 5 pens(1 bird per pen). The dietary treatments were; Treatment 1 : Control(Basal diet), Treatment 2 : $60\%$ Basal+4$40\%$ FW, Treatment 3 : $60\%$ $Basal+20\%\;FW+20\%$ AFW(Aspergillus oryzae inoculate dried food-waste diet) and Treatment 4: $60\%$ Basal+$40\%$ Am. Digestibility of treatment 2 was lowed on common nutrients and amino acids compared with control(p<0.05) and on crude fat and phosphorus compared with AFW treatments(T3, T4)(plt;0.05). Digestibility of treatment 3 and 4 increased on crude fiber and crude ash compared treatment 2 (p<0.05). Digestibility of control was high on agrinine, leucine, and phenylalnine of essential amino acids compared with treatment 3 and 4(p<0.05), and diestibility of treatment 3 and 4 was improved on arginine, lysine, and threonine of essential amino acids. Finally, despite comparable nutrient utilization among treatments, birds fed the dietary treatment containing AO tended to superior nutrient digestion to those fed the $60\%$ Basa1+$40\%$ FW.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.43 no.6
• /
• pp.679-686
• /
• 2010

To investigate the contribution of macroalgae to biogeochemical nutrients and carbon cycles, we measured the uptake rates of nutrients and $CO_2$ by Undaria pinnatifida using an incubation method in an acrylic chamber. From January to March 2010, U. pinnatifida was sampled at Ilkwang, a well-known area of macroalgae culture in Korea. The initial and final concentrations of nutrients, dissolved oxygen, total alkalinity, and pH of the chamber water were measured, and production/uptake rates were calculated using concentration changes, chamber volume, and incubation time. The production rate of dissolved oxygen by U. pinnatifida (n = 32) was about $5.4{\pm}4.0\;{\mu}mol\;g_{fw}^{-1\;}h^{-1}$. The uptake rate of total dissolved inorganic carbon (TDIC), calculated by total alkalinity and pH, was $7.9{\pm}6.5\;{\mu}mol\;g_{fw}^{-1}\;h^{-1}$. Nutrients uptake averaged $141.7{\pm}119.2$ nmol N $g_{fw}^{-1}\;h^{-1}$ and $15.0{\pm}9.1$ nmol P $g_{fw}^{-1}\;h^{-1}$. A positive linear correlation ($r^2$ = 9.6) existed between the production rate of dissolved oxygen and the uptake rate of total dissolved inorganic carbon, suggesting that these two factors serve as good indicators of U. pinnatifida photosynthesis. The relationships between fresh weight and uptake rates of nutrients and $CO_2$ suggested that younger specimens (<~50 g fresh weight) are much more efficient at nutrients and $CO_2$ uptake than are specimens >50 g. The amount of carbon uptake by the total biomass of U. pinnatifida in Korea during the year of 2008 was about 0.001-0.002% of global ocean carbon uptake. Thus, more research should be focused on macroalgae-based biogeochemical cycles to evaluate the roles and contributions of macroalgae to the global carbon cycle.

• The KSFM Journal of Fluid Machinery
• /
• v.12 no.3
• /
• pp.19-25
• /
• 2009

InThe purpose of this work is to analyze the flow characteristics and aerodynamic noise generated from a shroud fan at a constant 2,100 rpm using LES and FW-H noise model provided in the commercial code, FLUENT. Velocity distributions around the shroud fan obtained by using FLUENT code show good agreement with experimental results. The sound pressure level is decreased by about 6 dB as the distance from the fan increases twice. The directivity at 1st BPF shows a tendency of increasing SPL toward the axis of rotation.