Inrush currents of induction generators due to abrupt connection to utility power networks

The squirrel-cage-type induction generator is suitable for small water power stations and wind power stations because of its simple and rugged structure, and low construction cost. However, the transient rush current flows into the primary and secondary windings when an induction generator is connected abruptly to a utility power network. The inrush current causes the voltage fluctuation in the power system. Therefore, electric power companies need a control method with low cost of the inrush current of the induction generator. Many properties of the inrush current must be known in detail. The factors affecting inrush currents are system voltages, control of the system voltage phase angle, rotary speed, residual magnetism of the core, and residual electric charge of the primary windings. In this paper, the inrush current is analyzed by the instantaneous value symmetrical coordinates. The experimental study of the inrush current using phase control equipment and a small induction generator is presented. The conclusions of this investigation are summarized as follows: (1) The factor that gives the strong influence on the inrush current is the voltage phase angle. (2) Although rotary speed changes from 0.9 to 1.15 times as much as the synchronous speed, the maximum value of the inrush current is nearly constant. (3) The maximum amplitude of the inrush current is definitely seen in the first or second wave.     

One stage operation for aneurysm of the diverticulum of the ductus arteriosus and coronary artery bypass grafting

The effect of ofloxacin (CAS 82419-36-1), dapsone (CAS 80-08-0), rifampicin (CAS 13282-46-1) and clofazimine (CAS 2030-63-9) on the generation of superoxide anions was studied in vitro. The drugs were incubated with a superoxide generating system (photochemical reaction between riboflavin and dianisidine). The change in optical density was measured. The optical density was increased with dapsone and ofloxacin and decreased in presence of clofazimine and rifampicin. This result indicates that ofloxacin and dapsone have an antioxidant property, whereas clofazimine and rifampicin behave as pro-oxidants.     

Broad-band extreme ultraviolet lithography with a wet-silylated and dry-developed resist

Broad-band extreme ultraviolet (1340nm) lithography (EUVL) has been examined. Exposure intensity at the broad-band of 1340nm was 20 times larger than at the conventional narrow-band of 13nm. Moreover, broad-band EUVL with a wet-silylated and dry-developed resist process has been investigated in order to obtain a high resolution of 0.1μm with high-aspect-ratio. Imaging experiments were performed using 32:1 reduction Schwarzschild optics illuminated with a synchrotron radiation light source from SORTEC ring. The exposure was done through a 0.1μm-thick SiN vacuum window, Mo/Si multilayer coated optics and without a Be filter. Silylation characterization and determination of optimum composition of the silylation solution have been performed using Fourier transform infrared spectroscopy (FTIR). Using broad band EUVL with the optimal wet-silylated and dry-developed resist, 0.1μm lines and spaces of 0.55μm-thick resist (aspect RATIO = 5.5) can be successfully delineated.     

Implementation and Verification of an Application with Active Path Selection in IPv6 Environment

The paper proposes a function of active path selection to the destination by users and implements the function into the FTP application by using the routing header defined in IPv6 specifications. It also develops the "support system for quality selection", which supports the selection by providing information on each path, experimentally. The details of the function and an implementation of the application also are described.     

Experiment and numerical simulation of bubbly two-phase flow across horizontal and inclined rod bundles

Experimental and numerical analyses were carried out on vertically upward air-water bubbly two-phase flow behavior in both horizontal and inclined rod bundles with either in-line or staggered array. The inclination angle of the rod bundle varied from 0 to 60° with respect to the horizontal. The measured phase distributions indicated non-uniform characteristics, particularly in the direction of the rod axis when the rods were inclined. The mechanisms for this non-uniform phase distribution is supposed to be due to: (1) Bubble segregation phenomenon which depends on the bubble size and shape; (2) bubble entrainment by the large scale secondary flow induced by the pressure gradient in the horizontal direction which crosses the rod bundle; (3) effects of bubble entrapment by vortices generated in the wake behind the rods which travel upward along the rod axis; and (4) effect of bubble entrainment by local flows sliding up along the front surface of the rods. The liquid velocity and turbulence distributions were also measured and discussed. In these speculations, the mechanisms for bubble bouncing at the curved rod surface and turbulence production induced by a bubble were discussed, based on visual observations. Finally, the bubble behaviors in vertically upward bubbly two-phase flow across horizontal rod bundle were analyzed based on a particle tracking method (one-way coupling). The predicted bubble trajectories clearly indicated the bubble entrapment by vortices in the wake region.     

View-based navigation using an omniview sequence in a corridor environment

View- and appearance-based approaches have recently been attracting the interest of those involved in computer vision research. We have already proposed a visual view-based navigation method using a model of the route called the ”view sequence,” which contains a sequence of front views along a route memorized in the recording run. In this paper, we firstly apply the omnidirectional vision sensor to our view-based navigation method and propose an extended model of a route called the ”omniview sequence.” Secondly we propose a map named the ”view-sequenced map” which represents an entire corridor environment in a building. A method for the automatic acquisition of a view-sequenced map based on the exploration in a corridor using both stereo and omnidirectional vision is also described. Finally experimental results of the autonomous navigation and the map acquisition are presented to show the feasibility of the proposed methods. Correspondence to: Y. Matsumoto (e-mail: yoshio@is.aist-nara.ac.jp)     

Thermal recovery of antioxidant activity from carnosol quinone,the main antioxidation product of carnosol

The antioxidant reaction of carnosol, a phenolic diterpene of sage and rosemary, produced ortho‐ and para‐quinone derivatives. Although the orthoquinone derivative of carnosol (CARQ) is stable in a lipophilic solution and has a very weak antioxidant activity, the thermal treatment of CARQ in lipid restored strong antioxidant activity. HPLC analysis of the thermal recovery reaction clarified that the strong activity was mainly due to the reproduced carnosol. A possible mechanism for the production of carnosol from CARQ is the self‐redox reaction of CARQ. Two of the oxidation products from CARQ in the thermal recovery reaction were identified to be rosmariquinone and dehydrorosmariquinone. Copyright © 2004 Society of Chemical Industry     

Naphthalene sulfonate formaldehyde (NSF)-resin derived carbon beads as an anode material for Li-ion batteries

Carbon beads have been prepared by the carbonization of naphthalene sulfonate formaldehyde (NSF) resin. The procedures for the preparation have been described in detail. The electrochemical performance of NSF carbon beads as an anode material for lithium batteries has been correlated with some carbonization factors such as the molecular weight of the precursor, the ramp rate, and final temperature, etc.     

Dissolution of Nb(C,N) in mild steel during annealing

A formula for the solubility products of Nb and C in mild steel containing small amount of Ti which has been annealed in the austenitic region for 90s is presented. This solubility product gives closer agreement than that calculated from Smith's formula based on long-term annealing. Fine ferrite grains were achieved by dissolving Nb(C,N) into the matrix during annealing due to the increased supercooling during the austenite → ferrite transformation.