• Journal of Microbiology and Biotechnology
• /
• v.15 no.1
• /
• pp.1-6
• /
• 2005

Optimal criterion for the scale-up production of schizophyllan, a fungal polysaccharide secreted by Schizophyllum commune, was investigated. For the production of the polysaccharide in a 150-l bioreactor, the culture conditions optimized in a 15-l bioreactor were applied to a 150-l bioreactor with scale-up process, by changing impeller speed and airflow rate. The optimized impeller speed in the 15-l bioreactor was 50 rpm in a technical medium based on barley. For establishment of the scale-up process, 3 kinds of criteria were used while the gas throughput number was kept constant, as follows; constant volume-related power input, constant tip speed of stirrer, and constant Reynolds number. In the 150-l bioreactor, the highest values for the maximum specific growth rate (1.17/day) and productivity (0.63 g/L${\cdot}$day) were achieved in the culture condition from constant volumerelated power input criterion.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.13 no.3
• /
• pp.82-88
• /
• 2005

This study was carried out to investigate on the change of NaCl content during the food waste composting and on the safety of food waste compost(FWC) manufactured by the non-stirrer sealed fermenter. Plant culture test with pepper crop was also performed to see the effect of FWC, which was produced by the G co. ltd., on the growth of peper and migration of NaCl in soil. The culture test was performed at the farmland in Chungnam National University. The results were as follows; the NaCl content was gradually accumulated during food waste composting process, probably through water evaporation. Sodium concentration was, however, remarkably decreased at the final stage due to the desalting effect by water which was concentrated on the ceil of the fermentor. The analysis of chemical properties and humidity parameters on the food waste compost revealed that the product is quite a good qualified one. More than 0.5 tons of FWC application on red pepper cultivation caused diminished effect on the yield and the accumulation of salts on soil.

• Journal of Korea Foundry Society
• /
• v.17 no.6
• /
• pp.538-544
• /
• 1997

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2001.10a
• /
• pp.297-300
• /
• 2001

Physical modeling technique is applied to investigate foam generation in molten aluminum. By using room temperature water with specially designed equipment, the effects of stirrer type, fluid viscosity(glycerine added to water) and stirring velocity on foam generation behaviors are intensively analysed The distribution and size of bubbles varied with each process parameters but the most important parameters are stirring velocity and fluid viscosity. The results obtained from physical simulation have been confirmed by actual aluminum foam generation experiment at various process variables.

• Proceedings of the KAIS Fall Conference
• /
• 2006.05a
• /
• pp.184-187
• /
• 2006

Nickel was plated electrolessly on 304L stainless steel powder. To obtain uniform coating and dispension of powder, the bath was continuously agitated with magnetic stirrer. The various pH and bath temperatures were studied. The conditions were in the range of $pH4{\sim}10$ and $45{\sim}65^{\circ}C$, respectively. The coating morphologies were examined by SEM/EDS tests. The optimum condition was pH9 at $55^{\circ}C$.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.1
• /
• pp.31-37
• /
• 2002

전자파 잔향실(Reverberating Shielded Enclosure)의 개념은 전자파 차폐실(Shielded Enclosure)에서 얻어진 측정결과를 개선하기 위하여 1968년도에 제안되었다. 이후 Reverberating 또는 Mode-Stirred Chamber는 EM Immunity 측정뿐만 아니라 EMI측정에서도 많이 적용되어 왔지만, 국제 표준 방식으로 적용되어 오지 못하다가 최근 EMI 복사 전력 측정 및 EM Immunity 측정시설로 유용하게 사용될 수 있다는 점이 부각되어 국제 표준 방식으로 적용하자는 분위기가 무르익어 이에 대한 활발한 논의가 계속되어 오고 있다. 이러한 전자파 잔향실을 이용하여 EMI 및 EMS 시험을 실시할 수 있는 방법을 규격화시키자는 제안이 '96년 프랑스 Mandelieu 국제 전자파 장해 특별위원회(CISPR:International Special Committee on Radio Interference)회의에서 검토된 후 '97년 일본 Yokosuka CISPR 회의에서 정식의제로 채택되었다. 이 안건에 대하여 대부분의 국가들이 제안 취지에 찬성하여 NWIP(New Work Item Proposal) 문서가 각국에서 회람되었다. 초기 전자파 잔향실은 전자파 장해 및 복사 내성 측정을 위한 대용시험 시설로서 1968년 미국 Mendes에 의해 전자파 차폐실 구조에 Stirrer를 이용하여 필드의 균일도를 확보할 수 있다는 전자파 잔향실 개념이 처음으로 제안되었다. 이후 이 분야의 연구는 미국 표준 기술 연구소(NIST: National Institute of Standard and Technology)등에서 연구가 활발히 진행되고 있으며, 국제 표준화 기구인 CISPR에서 전자파 장해 및 내성 시험을 위한 대용시험 시설로서 활용하기 위하여 규격 작업이 진행중에 있다. 또한 최근 전자파 장해 방지를 위한 규제 주파수가 1∼18㎓ 까지 확장됨에 따라 이 주파수 대역에서 시험장으로 활용할 수 있는 전자파 잔향실이 새롭게 부각되고 있다. 전자파 잔향실은 기본적으로 공진 모드를 활용하기 때문에 일정한 크기의 잔향실 내부에서 전자파 균일성을 확보할 수 있는 모드 수에 의해 하한 주파수가 결정되며 충분한 모드 분포상태에서 Stirrer를 사용하여 필드 경계를 이동시킴으로서 확률적으로 균일한 필드분포를 확보하게 된다. 주파수가 증가함에 따라 모드수는 증가하기 때문에 하한 주파수 이상의 대역에 대한 시험시설로 활용할 수 있으며, 특히 ㎓ 대역에서 사용하기에 적합한 대용시험시설이라고 볼 수 있다.

• KSBB Journal
• /
• v.10 no.4
• /
• pp.401-405
• /
• 1995

An open pond type photobioreactor for mass cultivation of S. platensis was designed and the growth parameters from different cultivation processes were compared. 0.30(1/day) of specific growth rate and 1.69(g/$\ell$) of maximum cell density were obtained from batch cultivation. In fed-batch cultivation, specific growth rate and maximum cell density were estimated as 0.22(1/day) and 1.75(g/$\ell$), respectively. Maximum biomass productively from continuous cultivation was obtained as 0.44 (g/$\ell$/day). It proves that an outdoors-mass cultivation of S. platensis considering optimal environmental condition is economically feasible. In addition, the biomass productivity was studied in two different mixing systems such as agitation and air sparging methods. The biomass productivity by an agitation method was better than that in an air sparging method.

• KSBB Journal
• /
• v.19 no.5
• /
• pp.406-409
• /
• 2004

Matrix Assisted Laser Desorption ionization Time of Flight (MALDI-TOF) was used for enzymes identification related to B -1,3-glucan synthesis. Agrobacterium sp. ATCC31750 was cultivated with two stage Continuous Stirrer Tank Reactor (CSTR) and the cells were harvested and their protein profiles were analysed by two dimensional electrophoresis. The specific enzyme spot was treated with trypsin and ana lysed by MALDI-TOF to get peptide molecular weight. The peptide molecular weights were matched with Agrobacterium tumefacience's Data Base from the matrix science site, then could identify the avaliable key enzymes. In this study, we identified key metabolite of synthesis of beta-1,3-glucan, such as glucose-6-phosphate isomerase, phosphoglucomutase, B-1,3-glucan synthase and glucokinase, and we also identified uracil phosphoribocyl transferase and Ribosome recycling factor also.

• Journal of Korean Elementary Science Education
• /
• v.20 no.1
• /
• pp.139-147
• /
• 2001

This paper is to study on the change of volume and temperature of the solution which mixed water with ethanol. And its main purpose is to examine closely how the volume changes, and to find the method to maximize the change of the volume. The summaries for results of the study are; First, we were known that water and ethanol are homogeneously mixed. But two solvents does not mix homogeneously by different specific gravity at early stages. Second, we could see that the volume changed large at homogeneous mixed water with ethanol by stirrer, the change of volume is the largest value when water mixed with ethanol in the ratio of one to one. Third, when water mixed with ethanol in the ratio of one to one, the change of temperature is very large by activated hydrogen bond. We conclude that it is the best result when ratio of water and ethanol is one to one and the solution is well mixed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.508-511
• /
• 2004

This study focused on the effect of autonomic microcapsules on the mechanical properties of structural material. Several types of microcapsules with healing agents were manufactured by varying agitation speed of high speed stirrer. The size distribution of microcapsules was measured by a particle size analzer. The epoxy specimens embedded with microcapsules were manufactured and the degree of cure of such epoxy specimen was measured by a differential scanning calorimetry. The tensile modulus and tensile strength in epoxy specimens embedded with microcapsules were evaluated in order to investigate the effects of microcapsules on mechanical properties of structural materials. The configuration of microcapsules and morphology of fracture surfaces for the epoxy specimen were examined by an optical microcope and a scanning electron microscope. According to the results, tensile strength of the epoxy specimen embedded with microcapsules was indicated a little reduction, but tensile modulus was not much affected on microcapsules.