• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04a
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• pp.637-642
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• 1995

For measuring the error motion of ultra-precision spindle, eliminating the geometric errors is a must. Unless it is achieved, geometric errors will be dominant in data. Here, the roundness error and alignment error between spindle and sensor are to be removed. That's because typical error range of such spindle is muchless than geometric one. A capacitive transducer of cylidricalshape was developed, which takes full advantage of the spatial-averaging effect by using large area compared tpo the geometric error. This idea was first proposed by Chapman and here it is modified for better performance with nomical gap of 50 .mu. m and with newly designed guards which encompass the respective sensor to rectify the electrical field distribution in good shape. The measurement system is made to get the orbit of Ultra-Precision Air Spindle which is supposed to have its runout under 1 .mu. m. The Calibration data of this sensor is presented and the spindle orbit from 2000rpm to 5500rpm is showed. It is quite reasonable to use this sensor in the range of 60 .mu. m with an accuracy of several tens of nm.

• Membrane and Water Treatment
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• v.3 no.4
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• pp.243-252
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• 2012

Tri-n-butyl phosphate (TBP) was used as carrier for the transport of Golden yellow and Cibacron LSG dyes through a hexane bulk liquid membrane. The transport efficiency of dyes by TBP was investigated under various experimental conditions such as pH of the feed phase (dyes solution), concentration of the receiving phase (NaOH solution), concentration of TBP in membrane, rate of stirring, effect of transport time, type of solvent, dye concentration in feed phase, effect of temperature.. The maximum transport dyes occurs at ratio of 1:1 TBP-hexane At pH 3.0 0.1 (feed phase) the transport dyes decreased. At high stirring speed (300 rpm) the dyes transport from the feed phase to the strip phase was completed within 60 minutes at $27^{\circ}C$. Under optimum conditions: Feed phase 100 mg/L dyes solution at pH 1.0 0.1, receiving phase 0.1 mol/L NaOH solution, membrane phase 1:1 TBP-hexane , Stirring speed 300 rpm and temperature $27^{\circ}C$, the proposed liquid membrane was applied to recover the textile effluent.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.363-366
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• 2001

This study was to investigate the effects of media components on the mycelial growth of Lentinus eclodes, including C-source. N-source, Inorganic salts, and c/N ratio. Glucose and yeast extract were selected as C-source and N-source, respectively. $KH_2PO_4,\;K_2HPO_4,\;MGSO_4,\;7H_2O$ as inorganic salts were added. When glucose concentration was 30g/L and yeast extract concentration was 20g/L, indicating that C/N ratio was 1.5, the cell mass was about 9g/L.

• The Korean Journal of Food And Nutrition
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• v.10 no.4
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• pp.528-532
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• 1997

A fermented squeezed-type paste was processed in order to highly effective utilization of cockle shell by-product, and improvement on rheological properties and texture of hydrolysate by used additives. The cockly shell by-products were homogenized with addition of water and enzymatically hydrolyzed at 5$0^{\circ}C$ for 8 hours added 4% Protease N.P.(Pacific Chemical Co.). And the hydrolysate was thermally treated for the purpose of flavor improvement, enzyme inactivation and pasteurization product at 10$0^{\circ}C$ for 1 hour, with 4% glucose. To make improvement of rheological properties, used complex additive with 0.5% alginic acid, 1% pectin and 0.2% agar were very effective. And stability of mixing was 98.1% after centrifuged at 10,000 rpm for 60 minutes. The chemical composition of moisture, total carbohydrate, total nitrogen and amino type nitrogen in the fermented squeeze-type cockle shell by-product paste were 57.7%, 20.6%, 1,458mg% and 1,187mg%, respectively. And the ratio of amino type nitrogen in total nitrogen was 81.4%.

• KSBB Journal
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• v.8 no.5
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• pp.452-456
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• 1993

This study was carried out to optimize the fermentation conditions for direct alcohol fermentation of xylose by Pichia stipitis CBS 5776. The best cell growth and the ethanol production were obtained under 0.05 VVM aeration and 300rpm agitation at $30^{\circ}C$ using 100 g/l xylose medium of the initial pH 5.0. In the above condition, the maximum specific growth rate and maximum cell concentration were 0.14hr-1 and $1.3 \times109$ cells/ml, respectively. Pichia stipitis CBS 5776 also produced 40.2g/l ethanol utilizing about 96% of 100g/l xylose after 72hr fermentation. At this point, the overall volumetric ethanol productivity was 0.56g/1-hr and the ethanol yield was 0.42 g-ethanol/g-xylose consumed, which corresponds to 82% of the theoretical yield.

• Particle and aerosol research
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• v.15 no.4
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• pp.139-148
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• 2019

This study was performed for the application of a high-speed centrifugal cyclone to shale gas mining process. This device uses the centrifugal force to control particles similar to typical cyclones, and the disk located inside the cyclone is forced to rotate using a motor. The pressure difference occurred during the rotating of disk. Hence, inflow rate was generated without a blower fan. In addition, flow rate increased with elevating rpm of motor. The installing the disk in multiple stages on the inner rotor increased the instantaneous disk outlet flow. Hence, the control efficiency of oil particle increased from 1.05% to 31.2%. By modifying the structure of the disk so that the air flow to the opposite direction of the cyclone, the control efficiency of oil particles increased to 81.5%. By increasing the capacity of the motor and the size of the disk, the flow rate was increased to 2.5 ㎥/min because the rpm of motor and pressure difference increased. As rpm of motor increased, the cut-off diameter (d_pc) became smaller. Unlike the Lapple's equation, d_pc was inversely proportional to the effective number of rotations (N_e). The control efficiency was maintained even if the concentration of oil particles increased, for this reason, the higher the oil concentration, the more particles were accumulated and controlled.

• Journal of Pharmaceutical Investigation
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• v.37 no.1
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• pp.23-26
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• 2007

Two crystal forms of cefuroxime axetil were obtained by the recrystallization from different organic solvents and characterized by differential scanning calorimetry (DSC), X-ray powder diffraction (XRD). It was confirmed that two crystal forms are identical. The dissolution patterns of these two forms were also checked in 0.07 N HCl at $37{\pm}0.5^{\circ}C$, 100 rpm for 180 minutes. The transformation during storage was also studied.

• Membrane and Water Treatment
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• v.10 no.5
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• pp.361-372
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• 2019

Effect of different alkane based solvents on the stability of emulsion liquid membrane was investigated using normal alkanes (n-hexane, n-heptane, n-octane and n-decane) under various operating parameters of surfactant concentration, emulsification time, internal phase concentration, volume ratio of internal phase to organic phase, volume ratio of emulsion phase to external phase and stirring speed. Results of stability revealed that emulsion liquid membrane containing n-octane as solvent and span-80 (5 % (w/w)) as emulsifying agent presented the highest amount of emulsion stability (the lowest breakage) compared with other solvents; however, operating parameters (surfactant concentration (5% (w/w)), emulsification time (6 min), internal phase concentration (0.05 M), volume ratio of internal phase to organic phase (1/1), volume ratio of emulsion phase to external phase (1/5) and stirring speed (300 rpm)) were also influential on improving the stability (about 0.2% breakage) and on achieving the most stable emulsion. The membrane with the highest stability was employed to extract acridine orange with various concentrations (10, 20 and 40 ppm) from water. The emulsion liquid membrane prepared with n-octane as the best solvent almost removed 99.5% of acridine orange from water. Also, the prepared liquid membrane eliminated completely (100%) other cationic dyes (methylene blue, methyl violet and crystal violet) from water demonstrating the efficacy of prepared emulsion liquid membrane in treatment of dye polluted waters.

• Journal of ILASS-Korea
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• v.27 no.3
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• pp.117-125
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• 2022

This study examines whether engine fuel efficiency is improved by optimization of the exhaust valve timing in a state where the intake valve timing has been optimized in a small turbo gasoline engine that has intake cams and exhaust cams with fixed valve opening periods. When the exhaust valve is opened late, the expansion stroke is longer, and the efficiency can be improved. A 2-cylinder turbo gasoline engine with 0.8 liters of displacement and an MPI (Multi Point Injection) fuel system was used. The engine was operated at 1,500 and 3,000 rpm, and the load conditions included a partial load of 50 N·m and a high load of 70 N·m. Data was recorded as the exhaust valve timing was controlled, and this was used to calculate the efficiency of combustion using a heat release, the fuel conversion efficiency, and the pumping loss. Results and the hydrocarbon concentrations in the exhaust gas were compared for each condition. Experiment results confirmed that additional fuel efficiency improvements are possible through exhaust valve timing control at 1,500 rpm and 50 N·m. However, in other operating conditions, fuel efficiency improvements could not be obtained through exhaust valve timing control because cases where the pumping loss and fuel/air mixture slip increased when the exhaust valve timing changed and the fuel efficiency declined.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.7
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• pp.1053-1060
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• 2015

In this study, the optimal operation factors for struvite crystallization for removing and recovering nitrogen and phosphorus from anaerobic digestive fluid of swine manure containing highly concentrated nitrogen was determined. Every experiment for the struvite crystallization reaction was conducted by placing 1,000 mL of digestion fluid in a 2,000 mL Erlenmeyer flask at various temperatures, pH, and mixing speed. Except for special circumstances, the digestion fluid was centrifuged (10,000 rpm, 10 min) and then the supernatant was used for the experiment at room temperature and 100 rpm. The optimal mole ratio of $PO_4{^{3-}}:Mg^{2+}$ was 1:1.5, and the pH effect ranging from 9 to 11 was similar, when mixed for 1 hour. Under this condition, the removal efficiency of $NH_4{^+}-N$ and $PO_4{^{3-}}-P$ was 40% and 88.6%, respectively. X-shaped crystal was observed by light and scanning electron microscopy. In addition, struvite crystal structure was confirmed through X-ray diffraction analysis.