Numerical study on mixing of sprayed liquid in an LNG storage tank

This paper presents a numerical method to simulate the mixing of heavier LNG sprayed on lighter layer. Numerical results for evolutions of flow field and density field are obtained in a rectangular computational domain which includes the vicinity of the liquid surface. At the surface boundary, uniform distributions of the fluid velocity and the density are assumed. Detail structure of flow caused by impingements of liquid drops are neglected. But, to trigger a realistic motion, a series of random numbers is employed. It is used as an initial distribution of the density near the surface. This method successfully gives a realistic simulation of the mixing process. Numerical results for mixing velocity shows good agreement with experimental data

Using System Dynamics to Simulate the Management of Operation and Maintenance of Ship Machinery under the Port Availability Constraints

The total cost of ship machinery operation (CT) must be kept at the minimum value while considering the safety from failure. This paper proposes a model to minimize the CT by endeavouring the value of minimum Reliability Index (RI) of the machinery. The minimum RI is the level of reliability of machinery where we need to take maintenance action after some period of operation time. The alteration of minimum RI causes the changes of the composition of CT, including running cost (Cr), maintenance cost (Cm) and downtime cost (Cd). This paper discusses the operation of pumps which are installed in the cooling system of main engine of ship. As constraint, the maintenance of the pumps is assumed only possible to be carried out in the particular available port. This study utilizes the System Dynamics (SD) to construct two kinds of proposed models of machinery operation. They are model 1, without forecasting and model 2, with forecasting of minimum RI. Model 1 results in minimum CT, while model 2 reaches a CT lower than the outcome of model 1

A New Test for the Absorption Mechanism of GPS Radio Sources Using Polarization Properties

We consider the use of polarization properties as a means to discriminate between Synchrotron Self-Absorption (SSA) and Free--Free Absorption (FFA) in GHz-Peaked Spectrum (GPS) sources. The polarization position angle (PA) of synchrotron radiation at high frequencies for the optically thin regime is perpendicular to the magnetic field, whereas it is parallel to the magnetic field at low frequencies for the optically thick regime. Therefore, SSA produces a change in PA of $90^{\circ}$ across the spectral peak, while FFA does not result in such a change. We analyzed polarization data from VLA observations for six GPS sources to see if such a change in PA was present. Our results indicate that there is no significant evidence for $90^{\circ}$ change in PA across the spectral peak, suggesting that FFA is more likely than SSA for low-frequency cutoffs in these sources

Fundamental study for constructing a system to assist the left visual field of older drivers - Effectiveness of the alternative of the left front side-view mirror by the central visual field -

The purpose of this paper is to establish the basics of the systems that assist visibility of the left visual field for older drivers. The display was located either the left which corresponded to a left side mirror, or within the central effective visual field. Participants performed multiple tasks where tracking task using a steering wheel was a primary task, and judgment of situations using a left or front display was a secondary task. How the display location affected the judgment performance was explored for both young and older adults. We counted the number of the warning during the tracking task and measured the percentage correct reaction to displayed stimulus and reaction sensitivity. We investigated how these measures ware affected by age and display location. Mean warning number during the tracking tasks, the percentage correct recognition of situations and d' was affected age and display location. The central display was found to increase the percentage correct recognitions of situations

Discovery of Enhanced Radiative Recombination Continua of He-like Iron and Calcium from IC 443 and Its Implications

We present deep observations of the Galactic supernova remnant IC 443 with the {\it Suzaku X-ray satellite}. We find prominent K-shell lines from iron and nickel, together with a triangle residual at 8--10~keV, which corresponds to the energy of the radiative recombination continuum (RRC) of He-like iron. In addition, the wavy residuals have been seen at $\sim$5.1 and $\sim$5.5~keV. We confirm that the residuals show the first enhanced RRCs of He- and H-like calcium found in supernova remnants. These facts provide robust evidence for the recombining plasma. We reproduce the plasma in the 3.7--10~keV band using a recombining plasma model at the electron temperature 0.65~keV. The recombination parameter $n_{\rm e}t$ ($n_{\rm e}$ is electron density and $t$ is elapsed time after formation of a recombining plasma) and abundances of iron and nickel are strongly correlated, and hence the errors are large. On the other hand, the ratio of nickel to iron relative to the solar abundances is well constrained to 11$^{+4}_{-3}$ (1$\sigma$). A possibility is that the large abundance ratio is a result of an asymmetric explosion of the progenitor star.Comment: 4 pages, 5 figures, published in Ap