• 한국항공우주학회지
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• 제33권11호
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• pp.74-79
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• 2005

액체로켓용 터보펌프 인듀서의 성능향상을 위해서 전진익형 인듀서를 설계하고 유동해석하였다. 전진익형 인듀서의 경우 형상의 특징상 후진익형 인듀서에 비해서 짧은 축길이에도 상대적으로 큰 익단 현절비를 가지고 있으며, 큰 현절비에서도 불구하고 수력효율의 저하가 없었다. 또한 전진익형 인듀서의 경우 일반적인 후진익형 인듀서에 비해서 인듀서 입구에서 발생하는 역류의 크기가 작고, 또한 인듀서 블레이드 팁에서의 국부적인 저압영역이 작은 영역에서 발생하는 것이 관찰되었다. 따라서 전진익형 인듀서의 경우 인듀서 입구의 정압이 높아서 흡입성능의 향상이 있을 것으로 판단되었다. 후진익형 인듀서의 경우 허브의 블레이드가 입구 유동을 교란하여 입구 역류가 커지지만, 후진익형 인듀서의 경우 이러한 교란효과가 없기 때문에 역류가 줄어든 것으로 나타났다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.625-630
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• 2001

The inducers in liquid-rocket engines are to increase the inlet pressure of the pump to avoid any malfunction due to cavitation. Inducers are typically designed to be operated with some amount of cavitation for the compactness of the turbopump system. Also, inducers are designed to produce low headrise to prevent the decrease of the overall pump efficiency due to the low efficiency of inducers. In the present paper, a computational study on the hydrodynamic behavior of the inducer for the rocket-engine turbopump are presented including the effect of the mass flow rate under the constant rotational speed. As the mass flow rate is decreased, the inducer showed better performance with strong back flows which may have deleterious effects upon the anti-cavitation ability. But the adopted inducer showed very low headrise with high volume flow rates, which may be caused by the small passage area near the trailing edge. The modified version of the present inducer is proposed and numerically evaluated, which in turn showed better results.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권2호
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• pp.96-99
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• 2006

In this study, we have attempted to determine the optimum concentration of inducers responsible for efficient laccase production by the white-rot fungus, Trametes sp. Variations in laccase activity were investigated with changing concentrations of 2,5-xylidine, syringaldazine, ABTS, and guaiacol. Enhancement of peak laccase activity was achieved via the combination of 2,5-xylidine with ABTS, syringaldazine, or guaiacol, resulting in increases of up to 359, 313, and 340%, respectively, as compared to control values. Among the tested inducers, the addition of 0.1mM of ABTS coupled with 1.0mM of 2,5-xylidine in the medium after 24 h of cultivation proved optimal with regard to laccase enzyme production.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.340-343
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• 2003

Soils contaminated by hazardous hydrophobic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), have become a major environmental issue due to toxic and carcinogenic properties of those compounds. In this work, we investigated effects of various metabolic inducers on phenanthrene biodegradation. Biodegradation tests were peformed with two different Pseudomonads: Pseudononrdia hydrocarboxydans (Gram positive) and Pseudomonas putida (Gram negative). Intermediates of phenanthrene metabolism (1-hydroxy-2-naphthoate, salicylate, catechol, phthalate and protocatechuate) were selected as inducers. The tests indicated that 1-hydroxy-2-naphthoate was the most effective inducer and enhanced the phenanthrene degradation rate up to 5.7 times, even though all the others also had induction ability to some extent. The effective induction could be achieved even at a low concentration of 1-hydroxy-2-naphthoate. Addition of metabolic inducers would be an attractive trick for the successful bioremediation of PAH-contaminated soil.

• 한국안광학회지
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• 제8권1호
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• pp.65-71
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• 2003

각막 상피세포는 정상적인 apoptosis과정을 거쳐 세포가 탈락하고 재생한다. 이러한 apoptosis에는 많은 요소들이 관여하여 세포가 사멸하는데 여러 가지 메커니즘이 관여한다. 본 연구에서는 세포고사 인자로 알려진 물질들을 각막 상피세포에서 apoptosis의 유도 여부를 다른 세포와 비교하여 각막 상피세포의 특성을 알아보고자 시행하였다. 본 연구에 이용된 세포고사 유도물질은 recombinant human cytokiness ($INF{\gamma}$, $TNF{\alpha}$, FASAb), actinomycin D. camptothecin, cycloheximide, dexamethasone와 etoposide이다. 이들을 세포에 48시간 처리한 후 세포독성을 MTT assay로 측정하였으며 세포고사는 Hoechst 33342 staining. Annexin V-FITC/PI staining 그리고 DePsipher assay를 이용하였다. 세포고사의 한 경로인 FAS-FAS ligand system에 대한 연구는 immunocytochemistry로 Fas protein 발현 여부를 조사하였다. 모든 유도인자는 농도의존적으로 세포고사를 유도하였는데 Actinomycin D. camptothecin와 etoposide는 제조사의 추천 농도보다 낮은 농도에서 세포고사가 유도되었고 반면에 cytokines, cycloheximide, dexamethasone은 더 높은 농도에서 세포고사를 유도하였다. FAS antigen은 대조군과 처리군 모두에서 발현되었으나 세포고사율에 비례하여 높게 발현되었다. 본 연구 결과 각막 상피세포는 RNA synthesis inhibitor와 topoisomerase inhibitors가 intracellular receptor-activators 보다 세포고사에 민감하게 나타나는 세포의 특성을 보였다.

• 한국유체기계학회 논문집
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• 제8권1호
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• pp.23-29
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• 2005

Steady and unsteady cavitation characteristics of turbopump inducer were investigated in this paper. To investigate the effect of blade angle on the inducer performance, three inducers with inlet tip blade angle of $7.8^{\circ},\;7.0^{\circ},\;6.1^{\circ}$, respectively, were tested. For $7.8^{\circ},\;7.0^{\circ}$ inducers in the non-cavitating condition, head decreased linearly with flow rate, but head-flow rate curve had a dip at the flow coefficient ${\psi}=0.065$ for $6.1^{\circ}$ inducer. Attached cavitation and cavitation surge were found in the $7.8^{\circ},\;7.0^{\circ}$ inducers in the cavitation tests. During the attached cavitation one cell rotated at the same rotational speed as that of the inducer. The cavitation surge did not rotate and the oscillating frequency was $7{\sim}20\;Hz$. From the curve of the critical cavitation number versus flow rate, it was found that the steady cavitation performance of $6.1^{\circ}$ inducer was much lower than that of $7.8^{\circ},\;7.0^{\circ}$ inducers.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.333-339
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• 2003

Steady and unsteady cavitation characteristics of turbopump inducer were investigated in this paper. To see the effect of blade angle on the inducer performance, three inducers with inlet tip blade angle of $7.8^{\circ},\;7.0^{\circ},\;6.1^{\circ}$, respectively, were tested. For $7.8^{\circ},\;7.0^{\circ}$ inducers in the non-cavitating condition, head decreased linearly with flow rate, but head-flow rate curve had a dip at the flow coefficient ${\Phi}=0.065\;for\;6.1^{\circ}$ inducer. Rotating cavitation and cavitation surge were found in the $7.8^{\circ},\;7.0^{\circ}$ inducers in the cavitation tests. During the rotating cavitation one cell rotated at the same rotational speed as that of the inducer. The cavitation surge did not rotate and the oscillating frequency was $7{\sim}20\;Hz$. From the curve of the critical cavitation number versus flow rate, it was found that the steady cavitation performance of $6.1^{\circ}$ inducer was much lower than that of $7.8^{\circ},\;7.0^{\circ}$ inducers.

• 한국해양생명과학회지
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• 제8권2호
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• pp.186-189
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• 2023

Uncoupling protein 1 (UCP1) is a unique mitochondrial membranous protein expressed in brown adipose tissue (BAT) in mammals. While its expression in response to cold temperatures and adipogenic inducers is well-characterized in mammals and human infants, the molecular characterization and expression of UCP1 in fish remain unexplored. To address this gap, we analyzed UCP1 expression in response to adipogenic inducers in a fish cell line, rainbow trout gonadal cells (RTG-2), and compared it with UCP1 expression in three mammalian preadipocytes, 3T3-L1, T37i, and WT1 exposed to the Peroxisome proliferator-activated receptor gamma (PPARγ) agonists, rosiglitazone (Rosi). In mammalian preadipocytes, UCP1 protein was highly expressed by Rosi, with an induction of adipogenesis observed in a time-dependent manner. This suggests that UCP1 plays a significant role in adipogenesis in mammals. However, RTG-2 cells showed no response to adipogenic inducers and exhibited only marginal expressions of UCP1. These results imply that RTG-2 cells may lack crucial responsive mechanisms to adipogenic signals or that the adipogenic response is regulated by other mechanisms. Further studies are needed to confirm these phenomena in fish preadipocytes when an appropriate cell line is established in future research.

• Mycobiology
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• 제41권1호
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• pp.47-55
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• 2013

Rhizoctonia solani, Fusarium solani, F. oxysporum, and Macrophomina phaseolina were found to be associated with root rott and wilt symptoms of faba bean plants collected from different fieldes in New Valley governorate, Egypt. All the obtained isolates were able to attack faba bean plants (cv. Giza 40) causing damping-off and root rot/wilt diseases. R. solani isolates 2 and 5, F. solani isolate 8, F. oxysporum isolate 12 and M. phaseolina isolate 14 were the more virulent ones in the pathogenicity tests. Biocontrol agents (Trichoderma viride and Bacillus megaterium) and chemical inducers (salicylic acid [SA] and hydrogen peroxide) individually or in combination were examined for biological control of damping-off and root rot/wilt and growth promoting of faba bean plants in vitro and in vivo. Both antagonistic biocontrol agents and chemical inducers either individually or in combination inhibited growth of the tested pathogenic fungi. Biocontrol agents combined with chemical inducers recorded the highest inhibited growth especially in case SA + T. viride and SA + B. megaterium. Under green house and field conditions, all treatments significantly reduced damping-off and root rot/wilt severity and increased of survival plants. Also, these treatments increased fresh and weights of the survival plants in pots compared with control. The combination between biocontrol agents and chemical inducers were more effective than used of them individually and SA + T. viride was the best treatment in this respect. Also, under field conditions, all these treatments significantly increased growth parameters (plant height and number of branches per plant) and yield components (number of pods per plant and number of seeds per plant, weight of 100 seeds and total yield per feddan) and protein content in both seasons (2010~2011 and 2011~2012). Faba bean seeds soaked in SA + T. viride and SA + B. megaterium were recorded the highest growth parameters and yield components. Generally, the combination between biocontrol agents and chemical inducers recorded the best results for controlling damping-off and root rot/wilt diseases in greenhouse and field with addition improved plant growth and increased yield components in field.

• Journal of Mechanical Science and Technology
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• 제18권3호
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• pp.481-490
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• 2004

Steady state flow calculations are executed for turbo-pump inducers of modern design to validate the performance of Tascflow code. Hydrodynamic performance of inducers is evaluated and structure of the passage flow and leading edge recirculation are also investigated. Calculated results show good coincidence with experimental data of static pressure performance and velocity profiles over the leading edge. Upstream recirculation, tip leakage and vortex flow at the blade tip and near leading edge are main sources of pressure loss. Amount of pressure loss from the upstream to the leading edge corresponds to that of whole pressure loss through the blade passage. The viscous loss is considerably large due to the strong secondary flow. There appears more stronger leading edge recirculation for the backswept inducer, and this increases the pressure loss. However, blade loading near the leading edge is considerably reduced and cavitation inception delayed.