• Asian-Australasian Journal of Animal Sciences
• /
• v.9 no.4
• /
• pp.411-420
• /
• 1996

Asia Triple HIn this study an attempt was made to determine the cost of producing fodders at Savar Dairy Farm (SDF). For this purpose, all seasonal fodders, such as Maize, Jowar, Cowpea and Oat and all perennial fodders, such as Para and Napier were studied. The highest acreage of land was allocated to high-land Para (33.8%) and the lowest acreage (2.7%) was devoted to Cowpea. Jowar attained the highest yield (74.2 tons) per hectare and Maize attained the lowest yield (25.8 tons/h). The highest cost per hectare was attributed to Jowar (TK. 20944.18) while the lowest cost was attributed to low-land para (TK. 10349.86). The cost of production of fodder per kilogram was the highest (TK. 0.66) for Maize and the lowest for Oat (TK. 0.24). The cost of production of low-land Para was much lower than that of high land Para. The per kilogram cost of silage production was the highest (TK. 0.71) for Maize and the lowest (TK. 0.31) was for Napier. The gross return analysis further showed that the highest net margin and B:C ratio were observed for Napier followed by Low-land Para, Jowar, Oat, Cowpea, High-land Para and Maize. Therefore, those fodders whose B:C ratios and yield/ha were higher should be allocated more area of land to stimulate increased returns to SDF in the future is suggested.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.19 no.6
• /
• pp.641-645
• /
• 1990

In order to study the influence of culture conditions on cell growth and lipid formation by Mucor sp, various carbon and nitrogen sources initial pH and C./N ratio of medium were investigated. Glucose was found to be suitable carbon source in terms of lipid yield and ${\gamma}$-linolenic acid(GLA) content. When NH4Cl and (NH4)2SO4 were used as nitrogen source lipid content was high(19-21%) but GLA content was low(15-17%) On the other hand when NaNO3 and KNO3 were used lipid content was low(about 13%) but GLA content was high(22-23%). The highest production of lipid was obtained at a C/N ratio of 40 using glucose and (NH4)2SO4 as carbon and nitrogen source respectively. it was found that lipid yield was high at pH4.6 Also this fungus did not grow at 35$^{\circ}C$ and lipid yield was highr at 15$^{\circ}C$ than $25^{\circ}C$.

• Journal of the Korea Concrete Institute
• /
• v.17 no.5 s.89
• /
• pp.843-852
• /
• 2005

Presently, test results and stress-strain models for poorly confined high-strength columns, more specifically for columns with a tie volumetric ratio smaller than $2.0\%$, are scarce. This paper presents test results loaded in axial direction for square reinforced concrete columns confined by various volumetric ratio lateral ties including low-volumetric ratio. Test variables include concrete compressive strength, tie yield strength, tie arrangement type, and tie volumetric ratio. Local strains measured using strain gages bonded to an acryl rod. For square RC columns confined by lateral ties, the confinement effect was efficiently improved by changing tie arrangement type from Type-A to Type-B. A method to compute the stress in lateral ties at the concrete peak strength and a new stress-strain model for the confined concrete are proposed. Over a wide range of confinement parameters, the model shows good agreement with stress-strain relationships established experimentally.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.4
• /
• pp.1-9
• /
• 2001

The soot yield has been studied by a premixed propane-oxygen-inert gas combustion in a specially designed disk-type constant-volume combustion chamber to investigate the effects of pressure, temperature and turbulence on soot formation. Premixtures are simultaneously ignited by eight spark plugs located on the circumference of chamber at 45 degree intervals in order to observe the soot formation under high pressures. The eight flames converged compress the end gases to a high pressure. The laser schlieren and direct flame photographs for observation field with 10 mm in diameter are taken to examine into the behaviors of flame front and gas flow in laminar and turbulent combustion. The soot volume fraction in the chamber center during the final stage of combustion at the highest pressure is measured by the in situ laser extinction technique and simultaneously the corresponding burnt gas temperature by the two-color pyrometry method. The pressure and temperature during soot formation are changed by varying the initial charge pressure and the volume fraction of inert gas compositions, respectively. It is found that the soot yield increases with dropping temperature and rising pressure at constant equivalence ratio, and that the soot yield of turbulent combustion decreases in comparison with that of laminar combustion because the burnt gas temperature increases with the drop of heat loss.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.37 no.5 s.113
• /
• pp.41-49
• /
• 2005

This paper deals the effect of anthraquinone (AQ) on the contribution of sulphidity in kraft pulping of sapwood. The pulping conditions namely- active alkali concentration, pulpingtime, temperature and liquor ratio were varied in low ($15\%$) and high ($30\%$) sulphidity. $0.1\%$ AQ was added in the low and high sulphidity pulping with varying active alkali concentration and cooking time. At optimum conditions, low sulphidity kraft process produced about $44\%$ pulp yield with kappa number of about 23. But in high sulphidity kraft process kappa number was reduced to about 20 at the same yield. An addition of AQ reduced alkali requirement by $2\%$ on oven dried raw material and cooking time by 1 hour to produce pulp yield of about $44\%$ at kappa number 20. AQ is more effective in low sulphidity pulping than the high sulphidity pulping. The breaking length of kraft-AQ pulp was slightly higher than that of kraft pulp.

• Journal of Biosystems Engineering
• /
• v.43 no.2
• /
• pp.110-118
• /
• 2018

Purpose: In this study, the potential for biogas production, degradation rates, and lag-phase of diauxic growth of carbohydrate-based material, which is one of the proximate compositions, were investigated. Methods: This study was conducted using starch as a carbohydrate-based material. In experimental condition 1, the biogas potential of carbohydrate-based material was measured. In experimental condition 2, the effect of feed to microorganism ratio (F/M ratio) on lag-phase of diauxic growth from carbohydrate-based material was tested. Biochemical methane potential tests were performed at five different feed to microorganism ratios (0.2, 0.4, 0.6, 0.8, and 1.0) under mesophilic conditions. The biogas production patterns, lag-phase, total volatile fatty acids to total alkalinity ratio (TVFA/TA ratio), and time required for 90 percent biogas production were used to evaluate biogas production based on the biochemical methane potential tests. Results: In experimental condition 1, unlike previous studies, biogas was produced in the TVFA/TA ratio ranging from 1.131 to 2.029 (approximately 13-19 days). The methane content in the biogas produced from the digesters was 7% on day 9 and increased rapidly until approximately day 27 (approximately 72%). In experimental condition 2, biogas yield was improved when the feed to microorganism ratio exceeded 0.6, with an initial lag-phase. Conclusions: Even if the TVFA/TA ratio was greater than 1.0, the biogas production was processed continuously, and the $CO_2$ content of the biogas production was as high as 60%. The biogas yield was improved when the F/M ratio was increased more than 0.6, but the lag-phase of carbohydrate-based material digestion became longer starting with high organic loading rate. To clarify the problem of the initial lag-phase, our future study will examine the microbial mechanisms during anaerobic digestion.

• Earthquakes and Structures
• /
• v.12 no.2
• /
• pp.201-211
• /
• 2017

This paper experimentally investigates the effect of yield strength of reinforcing bars and stirrups on the seismic performance of reinforced concrete (RC) circular piers. Reversed cyclic loading tests of nine-large scale specimens with longitudinal and transverse reinforcement of different yield strengths (varying between HRB335, HRB500E and HRB600 rebars) were conducted. The test parameters include the yield strength and amount of longitudinal and transverse reinforcement. The results indicate that the adoption of high-strength steel (HSS) reinforcement HRB500E and HRB600 (to replace HRB335) as longitudinal bars without reducing the steel area (i.e., equal volume replacement) is found to increase the moment resistance (as expected) and the total deformation capacity while reducing the residual displacement, ductility and energy dissipation capacity to some extent. Higher strength stirrups enhance the ductility and energy dissipation capacity of RC bridge piers. While the product of steel yield strength and reinforcement ratio ($f_y{\rho}_s$) is kept constant (i.e., equal strength replacement), the piers with higher yield strength longitudinal bars are found to achieve as good seismic performance as when lower strength bars are used. When higher yield strength transverse reinforcement is to be used to maintain equal strength, reducing bar diameter is found to be a better approach than increasing the tie spacing.

• Korean Journal of Plant Resources
• /
• v.18 no.3
• /
• pp.512-517
• /
• 2005

To establish the economical cultivation method of Gastrodia elata Blume by controlling the shading rate and the mixing ratio of recycling spawn bed logs, a serial experiment was carried out. When G. elata was grown in the field with no shading, the yield of spawn tuber was higher than that of tuber of G. elata. The yield of G. elata was high in the rainproof green house covered with one layer of $95\%$ shading net, in the rainproof green house covered with two layers of $95\%$ shading net, and in the field with no shading, in that order. In the case of mixing ratio of recycling spawn bed logs, the yield was high in the fresh logs, in the mixing ratio of 2:1, and the ratio of 1:1, in that order. The income of the rainproof green house covered with one layer of $ 95\%$ shading net which brought the best yield was $81\%$ in the mixing ratio of 2:1 over the fresh logs.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.2
• /
• pp.10-21
• /
• 2015

For the safe design of steel-concrete composite structure, usable yield strength of steels are limited in most of design standard. However, this limitation sometimes cause the uneconomical design for some kind of members such as slender columns which was affected by elastic buckling load. For the economical design for slender columns, parametric study of RCFT (Rectangular CFT) with high-strength steel is conducted, especially investigating the limitation of yield strength of high-strength steels. Using ABAQUS, finite element analysis program, the finite element model was constructed and calibrated with experimental study for RCFT with high strength steel which have yield strength up to 680MPa. Investigated design parameters are yield strength of steel, compressive strength of concrete, steel thickness and slenderness ratio. The effect of design parameters were compared with design standard, KBC-09. From the parametric study with 54 models and previous test specimens, RCFT can be safely design with higher yield strength of steels than currently limited by KBC for large range of slenderness ratio.

• Korean Journal of Agricultural Science
• /
• v.20 no.2
• /
• pp.117-124
• /
• 1993

This study was conducted to determine the effects of alternating planting systems of soybean and tillering hybrid corn on yield of both crops. The planting systems included monocultures of both crops. 1 to 1 row ratio, 1 to 2 row ratio, 1 to 3 row ratio, 2 to 1 row ratio, 2 to 3 row ratio, 3 to 1 row ratio, 3 to 2 row ratio and 3 to 3 row ratio of soybean and corn. The results obtained are summarized as follows : The plant height of soybean was increased as the number of planting rows of corn increased. But the plant, height of soybean was quite stabilized when the ratio of soybean planting rows increased. When the plant height of soybean was increased due to the increased row number of corn, the branch number and diameter of soybean decreased and lodging ratio increased. Total fresh weight of soybean per 10a was decreased as the ratio of soybean planting decreased and it was increased when the ratio of soybean planting increased over monoculture of soybean. Dry weight of soybean per 10a showed the same tendency of the fresh weight. But the highest grain yield of soybean was obtained in the monoculture of soybean and it was 276 kg/10a. Comparatively high yield of soybean was obtained in the systems of 2 to 1 and 3 to 3 ratios. The plant height, number of tillers and number of ears per plant of tillering corn were greatly affected by the alternating planting of soybean and they were 208.9cm, 2.1 and 4 per plant, respectively. The fresh and dry weights and yield of corn per 10a showed significant differences among systems. The average fresh and dry weight of corn in the systems of 3 to 1 and 2 to 1 were 1000 kg and 100 kg higher than those of monoculture of corn. The kernel yields of corn per 10a were 438 kg in the monoculture system and 530 kg in the systems of 3 to 2 and 2 to 1. The total fresh weights of corn and soybean in systems of 3 to 1, 3 to 2 and 2 to 1 were higher than 5721 kg of soybean and 4358 kg of corn in the monoculture. Combined dry weight was high in the order of monoculture, 2 to 1 and 3 to 1 row ratios. Combined grain yield was high in the systems of 2 to 1 and 3 to 1 row ratios and it was over 430 kg per 10a.