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Aspen Dynamics(TM)와 ACM을 이용한 용융탄산염 연료전지 시스템의 모사 및 제어
전경연 ( Kyoung Yein Jeon ),곽하연 ( Ha Yeon Kwak ),경지현 ( Ji Hyun Kyung ),이태원 ( Tae Won Lee ),문길호 ( Kil Ho Moon ),이기풍 ( Gi Pung Lee ),류아림 ( Ah Rim Yoo ),양대륙 ( Dae Ryook Yang ) 한국화학공학회 2011 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.49 No.4
Recentincreasing awareness of the environmental damage caused by the CO2 emission of fossil fuelsstimulated the interest in alternative and renewable sources of energy. Fuel cell is a representative example of hydrogen energy utilization. In this study, Molten Carbonate Fuel Cell system is simulated by using Aspen(TM). Stack model is consisted of equilibrium reaction equations using ACM(TM)(Aspen Custom Modeler). Balance of process of fuel cell system is developed in Aspen Plus(TM) and simulated at steady-state. Analysis of performance of the system is carried out by using sensitivity analysis tool with main operating parameters such as current density, S/C ratio, and fuel utilization and recycle ratio. In Aspen Dynamics(TM), dynamics of MCFC system is simulated with PID control loops. From the simulation, we proposed operation range which generated maximum power and efficiency in MCFC power plant.
Yuan Yee Lee,Yein Oh,Min-Soo Seo,Min-Goo Seo,Jee Eun Han,Kyoo-Tae Kim,Jin-Kyu Park,Sung Dae Kim,Sang-Joon Park,Dongmi Kwak,Man Hee Rhee 고려인삼학회 2023 Journal of Ginseng Research Vol.47 No.5
Background: The anti-platelet activity of the saponin fraction of Korean Red Ginseng has been widelystudied. The saponin fraction consists of the panaxadiol fraction (PDF) and panaxatriol fraction (PTF);however, their anti-platelet activity is yet to be compared. Our study aimed to investigate the potency ofanti-platelet activity of PDF and PTF and to elucidate how well they retain their anti-platelet activity viadifferent administration routes. Methods: For ex vivo studies, Sprague-Dawley rats were orally administered 250 mg/kg PDF and PTF for 7consecutive days before blood collection via cardiac puncture. Platelet aggregation was conducted afterisolation of the washed platelets. For in vitro studies, washed platelets were obtained from Sprague-Dawley rats. Collagen and adenosine diphosphate (ADP) were used to induce platelet aggregation. Collagenwas used as an agonist for assaying adenosine triphosphate release, thromboxane B2, serotonin,cyclic adenosine monophosphate, and cyclic guanosine monophosphate (cGMP) release. Results: When treated ex vivo, PDF not only inhibited ADP and collagen-induced platelet aggregation,but also upregulated cGMP levels and reduced platelet adhesion to fibronectin. Furthermore, it alsoinhibited Akt phosphorylation induced by collagen treatment. Panaxadiol fraction did not exert any antiplateletactivity in vitro, whereas PTF exhibited potent anti-platelet activity, inhibiting ADP, collagen, andthrombin-induced platelet aggregation, but significantly elevated levels of cGMP. Conclusion: Our study showed that in vitro and ex vivo PDF and PTF treatments exhibited differentpotency levels, indicating possible metabolic conversions of ginsenosides, which altered the content ofginsenosides capable of preventing platelet aggregation.
Farooq Ahmed,Tae Jo Ko,Lee Jongmin,Yein Kwak,In Jun Yoon,S. Thirumalai Kumaran 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.7
Materials with high hardness are usually difficult to machine, and accomplishing precise and economical machining depends on all the cutting conditions. Appropriate tool geometry is one important aspect for the cutting process that can be optimized based on the machining parameters. In this study, the finite element simulation method was applied to analyze the effects of tool geometry on the cutting forces and tool temperature during the ball end milling of tool steel (AISI H13). Multiobjective optimization of the geometrical parameters was performed using the grey relational method, which gave a set of input parameters to obtain the minimum cutting forces and temperature. The findings of this work could be used as a basis for tool design. Experiments were conducted with mono-objective and multi-objective optimal geometries to validate the finite element analysis. The finite element and experimental results were both congruous with an error limit of 5%.