No abstract available

[en] In order to fully understand the fluid mechanics and heat transfer of lithium in a fusion reactor blanket, a study has been made on the steady incompressible MHD channel flow and heat transfer in the developing region of a parallel-plate channel. The magnetic field is uniform, but its direction makes an arbitrary angle with the channel axis. Because the velocity entrance length is short in a strong magnetic field, the complete Navier-Stokes equations have been employed. Vorticity and magnetic vector potential are introduced such that all of the governing equations can be written in a single form. These equations have been solved numerically by the method of upwind differences which allow solutions up to large Reynolds and Hartmann numbers. 21 refs

[en] An analytical study is presented of the effects of a transient magnetic field on a developing flow in a parallel plate channel (MHD flow). The flow is initiated by a steady field, which may experience exponential decay or growth or sinusoidal variations. Vorticity and stream functions govern the flow, along with the magnetic variables. The study is conducted for a fixed Re and Hartmann number (for the insulating channel). The complete Navier-Stokes and induction equations are considered in generating velocity profiles for three types of magnetic field variations. Small velocity overshoots are predicted, with hysteretic adjustments as the variations in the mean flow rate balance the changes in the Lorentz force caused by the field variations

[en] A compartmental model to describe mucociliary transport and particle clearance in the tracheobronchial trees was described. A method was proposed for determining the mucociliary transport rate as a function of the airway depth from the retention curve directly. Each airway generation was represented by an escalator. For Weibel's lung model there were 17 airway generations in the tracheobronchial tree. The subject performed a series of respiratory mechanical function tests prior to exposure to a monodisperse ferric-oxide aerosol tagged with technetium-99. The model was simple and appeared to describe the physical process well

No abstract available

[en] The accuracy of the dose planning system (Leksell GammaPlan) used in Gamma Knife (model-B) radiosurgery was verified using both the GafChromic films MD-55 (improved) and the EGS4 Monte Carlo technique. The Monte Carlo technique was employed to calculate the dose distribution along the x-, y- and z-axes when a single shot with opening of all 201 sources was delivered at the centre of a simulated water phantom with a diameter of 160 mm. Collimator helmets with different size of the Gamma Knife unit were verified. Good consistency (typical discrepancy less than 2%) was obtained between the results of Monte Carlo and GammaPlan. Small discrepancies, however, were obtained by GafChromic films. Discrepancies, as great as 10% when using the 4 mm collimator helmet, at the low percentage isodose curve along the z-axis of the measurement results were probably due to the small energy dependency of the GafChromic films. Significant discrepancies were not observed along x- and y-axes because such small discrepancies were easily over-washed by other gamma beams coming from the x- and y-directions. Similar results showing the discrepancies between the GafChromic films and GammaPlan were obtained when using the 8, 14 and 18 mm collimator helmets. However, the discrepancies along the z-axis became smaller as scattering effect increased when using larger collimator sizes. We suggest that the Monte Carlo technique should also be applied in stereotactic dose planning system verification as it is an ideal and reliable computational technique

[en] The accuracy of the dose planning system (Leksell GammaPlan), used in Gamma Knife (type B) radiosurgery at extreme irradiation depths, was verified using the Monte Carlo technique. EGS4 Monte Carlo calculations were employed to calculate the dose distribution along the x, y and z axes for an irradiation relatively shallow in a spherical bony cavity water phantom. Two different sizes of the collimator helmets, 8 and 18 mm, of the Leksell Gamma Knife Unit were studied. The results of GammaPlan showed good consistency with the Monte Carlo results. Furthermore, small dose enhancements were observed in the skull bone where accurate dose measurements are difficult due to the presence of the air-phantom interface. Therefore, the results of this project can promote confidence to all Gamma Knife centres in the world when using the Leksell GammaPlan

[en] A combined thermodynamic cycle using nuclear and hydrogen energy as heat sources was investigated in this paper. The cycle is composed of top cycle using HTGR as energy source and helium as working medium and a bottom cycle with H₂/O₂ direct combustion product as working substance. hydrogen and oxygen are thermochemically by splitting of water produced through a part of nuclear heat recovered from the top cycle. They may be delivered to the O₂/H₂ users or used as fuels for the high temperature bottom Rankine steam cycle. The combined cycle not only uses the new energy sources instead of conventional fossil fuels but it possess the advantages of both helium and steam cycle. It has a high thermal efficiency, large unit capacity, many-sided usage and less pollution. It may represent a new type of combined cycles for future energy conversion and power generation. Using computer diagram, a variety of schemes were calculated and analyzed. The influence of some main parameters upon the cycle performance were also studied

[en] In order to qualitatively understand the mechanics of heat transfer in a fusion reactor blanket containing lithium, a study is made in this paper of heat transfer in the entrance region of a parallel plate channel under the influence of a uniform magnetic field. Since liquid metals have a high thermal conductivity, axial heat conduction is important and cannot be neglected. Hence the complete energy equation without boundary layer simplifications is considered. Trapping of neutrons by the blanket fluid is represented by a uniformly distributed volumetric heat source. The problem has been solved numerically using finite differences for the constant wall temperature and constant wall heat flux cases. Developing temperature profiles and Nusselt numbers in the entrance region are determined as a function of Peclet number and heat generation parameter. Results for an inclined magnetic field can be deduced from that for a transverse magnetic field

[en] CHINSHAN unit 1 recirculation suction line 0.1 ft² small break LOCA(SBLOCA) is analyzed in this study by using the RETRAN-02 code. The analytical results show that the High Pressure Core Injection (HPCI) system is capable of assuring core coverage after this SBLOCA