[en] To predict the thermal-hydraulic transients, an analytical method has been developed for single and two-phase flow in arbitrary piping networks. In this method the piping network is represented by vessels and flow channels. The thermal-hydraulic transients in the channel are described by partial differential equations derived from mass, momentum and energy conservation laws. The partial differential equations are solved implicitly, simultaneously for the whole network, with the ordinary differential equations that describe the change of vessel pressures and enthalpies. Numerical calculation error is evaluated in the implicit method for the integration of partial differential equations of channel flow. In the numerical calculation an artificial diffusion appears with a diffusion coefficient δtlambda₂/2, where δt is a time step and lambda denotes the propagation velocity of the perturbation. (orig.)

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[en] A computer code 'CIDER' was developed which analyzes radiant heat transfer in a BWR fuel rod bundle under loss of coolant conditions. In the code, (1) a channel box and fuel rods are considered to be gray bodies, (2) reflection and absorption of radiation beams in the atmosphere is neglected, (3) a fuel rod is approximated by a regular polygonal rod, and (4) radiant heat flux is calculated considering circumferential temperature distribution on each fuel rod surface, which is determined from radial and circumferential heat conduction calculations in a fuel rod. It was found that the conventional model with uniform cladding temperature overestimated heat flux about 30% in a typical situation, or correspondingly underestimated the temperature rises. (Auth.)

[en] The results of high spatial resolution mapping observations of CO emission from the bipolar nebula CRL 2688 are reported. The CO spectrum toward the center shows line wings with a full width of 85 km/s. On the blueshifted wing, a narrow and deep absorption feature is seen at a velocity shifted by 20 km/s from the systemic velocity. A central compact core elongated perpendicularly to the bipolar axis and blueshifted high-velocity emission distributed along the optical lobes suggest the presence of an expanding disk of molecular gas and fast stellar wind as the acceleration agent. The absorption feature suggests that an expanding cold absorbing envelope surrounds the relatively warm molecular envelope. The absorbing envelope has an excitation temperature lower than about 5 K and an optical depth larger than 1.2 in the CO(J = 1-0) line, and it is expanding at 20 km/s. The size of this envelope is larger than about 0.6 pc and its mass is larger than 0.016-0.044 solar mass. 16 references

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[en] A computer program FOSTER has been developed for transient analyses in nuclear power plants. Instead of modeling individual plant components, FOSTER is composed of the calculational function modules necessary to simulate the plants. These modules calculate reactor kinetics, heat transport by single phase flow, heat transport by two phase flow, heat conduction in walls, heat generation and conduction in fuel elements, and response of control systems. A plant model is represented by the combination of these modules in accordance with input data. When a plant model modification is necessary, only the input data need be changed, no program alternation is required. Moreover stable numerical methods (method of characteristics and partially or fully implicit scheme) are adopted, so we can also select appropriate time step sizes according to the required accuracy and the analysis phenomena. Therefore, the program is flexible, and various transients e.g., reactivity insertion, loss of flow, loss of piping integrity can be analyzed for various types plants e.g., FBRs, LWRs, HTGRs

[en] Aperture synthesis observations of the central 1.5 kpc region of the spiral galaxy Maffei 2 have been made in CO(J = 1-0) line. A central narrow ridge of molecular gas with a size 1000 pc x 200 pc and a ringlike feature with a large noncircular motion (60 km/s) with a size 500 pc x 240 pc have been found. The narrow ridge is interpreted as a bar of molecular gas in shocks generated at the leading edges in the bar potential. The observational results suggest that the ring is an expanding and rotating ring of molecular gas in the plane of the galaxy. The ring may have been formed by a starburst induced by the efficient gas supply in the bar potential. 38 refs

[en] We have observed the CO bipolar flow source near NGC 2071 in the J = 1-0 line of carbon monosulfide with 30'' resolution provided by the new 45 m Nobeyama telescope. We find a compact cloud with a size of approx.0.3 pc x 0.15 pc embedded in an extended cloud. This compact molecular cloudd is more than 4 times smaller than ws indicated in previously published coarser resolution observations, is elongated orthogonally to the bipolar flow, and shows strong signs of rotation. However, we estimate the mass of the compact cloud to be approx.10 M/sub sun/, much less than expected if it has been focusing the flow. We therefore conclude that collimation of the flow is taking place at considerably smaller scales unresolved with the 30'' beam

[en] By using the 45 m millimeter-wave telescope, we have observed the CO bipolar flow source associated with an infrared source, GL 490, in the J = 1-0 line of carbon monosulfide. The high angular resolution of the telescope, 30'', has allowed us to find a compact CS cloud about 0.3 pc x 0.13 pc in extent around GL 490, which is elongated orthogonally to the direction of the CO bipolar flow. Part of the cloud shows signs of expansion at velocities of < or approx. =4 km s^-1, although the total outgoing momentum of the CS cloud is smaller than that of the CO flow by an order of magnitude. This implies that the CS compact cloud has not been responsible for collimating the bipolar flow in this object