• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.11c
• /
• pp.613-622
• /
• 2000

Watering operation for oyster mushroom growing houses is regarded as drudgery and time consuming farm operation for growers. Most of mushroom growing beds in oyster mushroom growing houses are designed as two-row with four floor beds, therefore the watering and ventilation between the bed floors are much difficult for farmers because of its structural design. The study aimed to reduce the watering operation and improve the mushroom growing environment through the humidification and air supply on mushroom growing beds. Results showed that appropriate size of nozzle is between 0.8~0.5ml/s for the humidification and higher than the 2.0ml/s for the watering. The optimum water supply pressure was regarded as between 1.0~2.0MPa and the uniform distribution of droplet on the bed showed on air flow speed of 14m/s. The prototype was equipped with twin nozzle with. the humidification nozzle of 0.85ml/s and watering nozzle of 5.0ml/s, and the air blast fan with the air speed of 10m/sec in each air spout. In the field test in a practical scale mushroom growing house, it was well operated dependant on the set desire by a electric control unit. The machine can be practically used as air blast watering and air blast humidification for oyster mushroom growing farms without manual.

• Microbiology and Biotechnology Letters
• /
• v.9 no.1
• /
• pp.35-44
• /
• 1981

Whole cell penicillin amidase of Escherichia coli was immobilized by entrapment in gelatin followed by extrusion and crosslinking with glutaraldehyde. The immobilized engyme preparation demonstrated the recovery yield of activity up to 70% and good stability during storage and operation. The half life of activity decay during the operation was estimated to be about 50 days. The optimum pH and temperature for both of immobilized and soluble enzyme are 8.5 and 5$0^{\circ}C$, respectively. No significant change was demonstrated in the effect of pH and temperature, but the increase in heat stability at high temperature was observed in the case of the immobilized enzyme. It was found that the plug flow reactor could be operated favorably since the pH drop along the column path due to tile reaction product was minimized by employing substrate solution with moderate buffer strength. The optimal condition of reactor operation was discussed with regard to the effect of substrate concentration and the residence time on the conversion efficiency and productivity.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.11
• /
• pp.1228-1237
• /
• 2005

In order to predict the long-term effects of pollutants in sediment on the water quality and the improvement of water quality according to dredging operation, models applied to decide the location and the propriety of dredging were developed. At first, the area was divided into several segments and the developed model was applied to simulate the behaviors of contaminants in an aquatic environment by using estimated parameters. And then through the sensitivity analysis between parameters, the optimum values were determined. The long-term modelling in the area A forecasted that PCBs concentration in the hot spot was decreased from $3.1\;{\mu}g/L$ to $2.4\;{\mu}g/L$ in 30 years. Contaminants in sediment as a source of water pollution did not reduce remarkably in the long run. Therefore it is difficult to expect the improvement of water qualities without the fundamental isolation of contaminants from sediment. It is considered that the selective dredging in the spot improves the water quality consequently.

• Journal of Korean Society on Water Environment
• /
• v.23 no.5
• /
• pp.607-612
• /
• 2007

In this study, we investigated the variations of the kinetic coefficients and Chemical Oxygen Demand (COD), N and P mass used for assimilation of a sequencing batch reactor (SBR) system with the variation of SRTs; SRTs of 7.5, 10.0, 12.5, 15.0 and 20.0 days were tested in one cycle of SBR operation to determine the optimum conditions for the operation of the SBR and estimate its COD, nitrogen and phosphorus removal efficiencies. The SBR system was operated under the conditions as follows: an operation time of 6 hours per cycle, a hydraulic retention time (HRT) of 12 hours, an influent COD loading of $0.4kg/m^3/day$, and an influent nitrogen loading of $0.068kgT-N/m^3/day$. The yield coefficient (Y) and decay rate coefficient ($k_d$) were estimated to be 0.4198 kgMLVSS/kgCOD and $0.0107day^{-1}$ by calculating the removal rate of substrate according to the variation of SRT. Considering total nitrogen amount removed by sludge waste process, eliminated by denitrification, and in clarified water effluent with reference to 150 mg/cycle of influent nitrogen amount, the percentage of nitrogen mass balance from the ratio of the nitrogen amount in effluent (N output) to that in influent (N input) for Runs 1~5 were 95.5, 97.0, 95.5, 99.5, and 95.5%, respectively, which is well accounted for, with mass balances close to 100%.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.4
• /
• pp.712-720
• /
• 1988

This paper describes some development of computer-aided system called "COLD-FORMING" and "DESIGN-DIE". "COLD-FORMING" is designed for the forming sequence and "DESIGN-DIE" for the die design of press forming rotationally symmetric parts. The computer program developed is used in interactive and written in BASIC. Design rules for process planning and die design are formulated from process limitations, plasticity theory and know-how of experience of the field. "COLD-FORMING" capabilities include (1) analysis of forming sequence and recognition of individual operation involved each step, (2) determination of intermediate shape and dimensions, (3) calculation of forming loads to perform each forming operation and (4) graphic out put for the operation sheet. "DESIGN-DIE" capabilities include (1) optimum die design corresponding to the output of "COLD-FORMING" and (2) graphic output for the die design.of "COLD-FORMING" and (2) graphic output for the die design.ie design.

• Journal of Korea Water Resources Association
• /
• v.44 no.12
• /
• pp.1001-1013
• /
• 2011

Development of an optimal water supply system considering water quantity, quality, and economical efficiency is needed to decide optimal available area by combine water supply systems in overlapped area where are more than 2 water sources. The EPAnet and the KModSim were coupled to develop optimal network model. The developed network model was calibrated by measured data from water supply system in Geoje City, Korea in 2007 which have three water sources such as Sadeong booster pumping station, Guchun dam reservoir and Yoncho dam reservoir. The optimum network model was validated by operating results of 2011 to assess the economically optimized service area and optimal pump combination under the given hydraulic operating rules developed in this study. The developed model can be applied into designing water supply systems and operating rules for the conjunctive operation since the model can give the optimal solution satisfied with water quantity, economical efficiency and quality.

• Journal of Korean Society of Transportation
• /
• v.24 no.4 s.90
• /
• pp.19-29
• /
• 2006

As the rapid increase of highway investments from Private sector the organizations of highway operator became diversified, and thus causing various unexpected problems. Highways invested by private capitals have different fare rates and managing systems. It is desirable to reduce drivers' inconvenience using more than two sections of highways spread over different jurisdictions. The main purposes of this research are i) data survey and problem statements ii) prediction of future problems and preparing appropriate countermeasures. This research are divided into two parts. They are management system and fare collection system. Major investigations of this study are as follows, optimum toll operation models depend on charging systems and interchange shapes of two interconnecting expressways. Assuming that the current payment and the new electronic payment system aye used concurrently for a while, some alternatives for the inter-operation to collect tolls ate suggested focusing on the efficiency to tollway corporations as well as convenience to drivers. The advantages and disadvantages of the alternatives, including their characteristics, are compared.

• Korean Journal of Food Science and Technology
• /
• v.20 no.3
• /
• pp.303-309
• /
• 1988

The heat generation at the start-up period of an autogeneous single screw extruder was determined with various feed materials, die structure and operational conditions. The highest heat generation rate was observed with defatted soybean meal, while the lowest value was obtained with rice flour, and wheat and barley flour showed the intermediate rate. As the moisture content of the flour decreased and the screw speed increased, the electric power requirement and heat generation rate increased. The temperature at compression section increased with the decrease in the particle size. The same effect was also observed as breaker plate was installed. The optimum operation was established as the temperature profile was maintained in decreasing order of metering section, die and compression section.

• Journal of Biosystems Engineering
• /
• v.36 no.3
• /
• pp.163-170
• /
• 2011

Analysis of load on major parts of the tractor power drive line is critical for efficient and optimum design of a tractor. The purpose of this study was to evaluate severeness of the tractor PTO driving axle during rotary tillage operation. First, S-N (stress vs. number of cycle) curve of a PTO driving gear was obtained through the fatigue life test using a PTO dynamometer. Second, PTO severeness was evaluated during rotary tillage operation. Torque measurement system was constructed with strain-gauge sensors to measure torque of a PTO axle, an I/O interface to acquire the sensor signals, and an embedded system to calculate severeness. The severeness of PTO was analyzed using measured torque data during rotary tillage. In the PTO gear life fatigue test, breakage time and bending stress of the gear were measured by tooth widths and torque change during the fatigue life test. The S-N curve showed a good linear relationship between bending stress and number of cycle (life) with a coefficient of determination of 0.97. For PTO severenss evaluation, rotary tillage operations were conducted at two PTO rotational speeds (level-1, level-2) under different paddy and upland field sites with different soil conditions. Results of averaged relative severeness for PTO level-1 and PTO level-2 were 1.96 and 3.34, respectively, at paddy field sites, and they were 1.36 and 2.51, respectively, at upland field sites. The results showed that the PTO driving axle experienced more severe load during rotary tillage at paddy fields than at upland sites, and relative severeness was greater at the higher PTO rotational speed under all of the soil conditions.

• Nuclear Engineering and Technology
• /
• v.33 no.4
• /
• pp.355-364
• /
• 2001

In order to evaluate and finally optimize the vitrification condition for combustible dry active waste (DAW), dust and gas generation characteristics were investigated for PE, cellulose, and mixed waste Tests were conducted by varying the operation variables such as melter configuration, excess oxygen amount, and waste feeding rate. Results showed that dust generation characteristics were affected by the operation parameters and the melter＇s configuration is the dominant one. For all tested DAWs, dust generation was reduced by increasing the waste feeding rate and the excessive oxygen amount in the melter. Among waste types, dust amount was decreased by the order of mixed wastes, PE, and cellulose. Other parameters such as temperature variation and operation time have also affected the dust generation. The optimum condition for the DAW vitrification was determined as the melter＇s configuration equipped for minimizing the waste dispersion with 20 kg/h of waste feeding rate and 100% of excessive oxygen supply. CO gas concentration in the off-gas was immediately influenced by the combustion state in the melter, but showed similar trend as the dust generation. For the NOx production during the vitrification process, thermal NOx, which is generated from the Post Combustion Chamber (PCC), rather than fuel NOx was assumed to be dominant. The gas cleaning of efficiencies of the PCC, wet scrubber, and Selective Catalytic Reduction system (SCR) were found to be high enough to keep the concentration of pollutants (CO, NOx, SOx, HCI) in the stack below their relevant emission limits.