• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1429-1435
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• 2021

The temperature distribution of an electromagnetic pump was analyzed with a flow rate of 1380 L/min and a pressure of 4 bar designed for the sodium thermo-hydraulic test in the Sodium Test Loop for Safety Simulation and Assessment-Phase 1 (STELLA-1). The electromagnetic pump was used for the circulation of the liquid sodium coolant in the Intermediate Heat Transport System (IHTS) of the Prototype Gen-IV Sodium-cooled Fast Reactor (PGSFR) with an electric power of 150 MWe. The temperature distribution of the components of the electromagnetic pump was numerically analyzed to prevent functional degradation in the high temperature environment during pump operation. The heat transfer was numerically calculated using ANSYS Fluent for prediction of the temperature distribution in the excited coils, the electromagnet core, and the liquid sodium flow channel of the electromagnetic pump. The temperature distribution of operating electromagnetic pump was compared with cooling of natural and forced air circulation. The temperature in the coil, the core and the flow gap in the two conditions, natural circulation and forced circulation, were compared. The electromagnetic pump with cooling of forced circulation had better efficiency than natural circulation even considering consumption of the input power for the air blower. Accordingly, this study judged that forced cooling is good for both maintenance and efficiency of the electromagnetic pump.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.7
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• pp.713-721
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• 2005

A marine diesel engine should realize optimal operation efficiency while reducing NOx, PM (Particulate Matters) and other emissions. Fuel injection systems that use electronic control can become an effective means of achieving that objective. However. it still needs some accurate and instant information in order to bring its ability into full potential while sailing on the sea. The important information of them are a shaft torque and continuous combustion pressures of all cylinders. The shaft torque and the propeller thrust described in this paper are measured at an intermediate shaft by using a unique principle that one of two electromagnet coils oscillates a vibrating strip which the length changes with force and the other coil picks up the change of the frequency of the vibrating strip. For further reference, the shaft power meter multiplied the torque by the shaft revolution has already had about 750 sets of sales performance. The research presented in this paper started about ten years ago and is concerned with the development of a combustion pressure sensor that uses the same principle. Recently, the pressure sensor which bears continuous operation has been developed after a hard struggle, that is, the system that consists of a shaft horsepower meter, a propeller thrust meter and a combustion pressure sensor has been completed and has been shown to be reliable. This paper describes the configuration of this system, the material of the combustion pressure sensor, the principle of that, and the improving point of the sensor, and, we finally consider the use of this system.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.405-413
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• 2004

The rheological properties of an exopolysaccharide, EPS-R, produced by the marine bacterium Hahella chejuensis strain 96CJ 10356 were investigated. The $E_{24}$ of $0.5\%$ EPS-R was $89.2\%$, which was higher than that observed in commercial polysaccharides such as xanthan gum ($67.8\%$), gellan gum ($2.01\%$) or sodium alginate ($1.02\%$). Glucose and galactose are the main Sugars in EPS-R, with a molar ratio of ${\~}1:6.8$, xylose and ribose are minor sugar components. The average molecular mass, as determined by gel filtration chromatography, was $2.2{\times}10^3$ KDa, The intrinsic viscosities of EPS-R were calculated to be 16.5 and 15.9 dL/g using the Huggins and Kraemer equations, respectively, with a 2.3 dL/g overlap. In terms of rigidity, the conformation of EPS-R was similar to that of caboxymethyl cellulose ($5.0{\times}10^{-2}$). The rheological behavior of EPS-R dispersion indicated that the formation of a structure intermediate between that of a random-coil polysaccharide and a weak gel. The aqueous dispersion of EPS-R at concentrations ranging from 0.25 to $1.0\%$ (w/w) showed a marked shear-thinning property in accordance with Power-law behavior. In aqueous dispersions of $1.0\%$ EPS-R, the consistency index (K) and flow behavior index (n) were 1,410 and 0.73, respectively. EPS-R was Stable to pH and salts.

• Journal of Life Science
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• v.25 no.7
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• pp.748-756
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• 2015

The report explores the possibility that the single extract of natural substances and the mixture of single extracts of natural substances create a synergy effect to increase the antimicrobial activity. It also compares the previous researches to find out if the natural medicinal herbs’ extract has antimicrobial activity on dandruff causative organism, Malassezia furfur. For the experiment on the mixture of single extracts of natural substances, the results are like following: 1. Staphylococcus aures’s antibacterial activity is resistant to mixture of three natural substances. 2. Escherichia coil’s antibacterial activity is resistant to mixture with Coptidis rhizoma. 3. Candida albicans’ antifungal activity is resistant to mixture with Chinese galls, which means the different results may be expected when tested with each germ. 4. On the other hand, Malassezia furfur has no antifungal activity on the single extract of natural substances and shows weak antifungal activity, whose diameter is 3.20 mm when tested with the mixture of 50% of Coptidis rhizoma and 50% of Phytoncide. The result is totally different from the one on the same eumycetes, C. albicans. That is because M. furfur has more lipophilic chemicaled cell walls than C. albicans does and it also consists of lamella layer, inner plasma membrane and intermediate multiple layers.