This paper reports on design and test fabrication of a poly-crystalline lanthanum hexa-boride (LaB₆) thermionic converter, and experimental results of the output power generation characteristics both in unignited and ignited mode operation, and the measurement of the LaB₆ emitter and the LaB₆ collector work function in cesium (Cs) vapor based on the data in unignited mode V-I characteristics.
Poly-crystalline LaB₆ emitter work function ø_E was obtained from the forward saturation current J_for in unignited mode V-I curves. The bare work function of the LaB₆ emitter ø_Ebare is 3.4 eV, and ø_E in Cs vapor is, for example, 2.68 eV at T_E/T_R=3.0, here T_E is the emitter temperature, T_R is the cesium reservoir temperature.
Poly-crystalline LaB₆ collector work function ø_c in Cs vapor was measured from the reverse saturation current J_rev in unignited mode V-I curves. Although ø_c depends on the emitter and/or the collector temperature, the minimum ø_c is 1.35 eV when T_c=720K, T_c/T_R=1.53, here T_c is the collector temperature.
The value of ø_cmin=1.35 eV is far less than the value of ø_cmin=1.6_??_1.7 eV of refractory metal collectors. Therefore the LaB₆ thermionic converter has possibility to greatly improve power generation efficiency of a thermionic converter.
The maximum power density of the LaB₆ thermionic converter in ignited mode operation was 0.39W/cm², when output voltage V=0.5V, output current density J=0.78A/cm², T_E=1, 746K, T_c=1, 018 K, T_R=454 K, and the interelectrode spacing d=1.1mm. The value of the barrier index was V_B=2.5eV.

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This paper presents modified approximation techniques in modal frame for frequency dependent effects of a double circuit DC transmission line on common tower.
Elements of transformation matrix and surge admittance are approximated with not only first but also second order transfer function. Also unstable terms are introduced. Addition of second order and unstable terms reduces approximation error. The transient calculation of the Bergeron type model with unstable terms was numerically stable.
Also the paper describes a new smoothig method based on eigen vector tracing technique for frequency dependent effects.

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In recent years, it is noticed that flashover faults of snow covered insulator string due to AC operating voltage or switching surge may occur in heavy snow areas.
AC, AC overvoltage, switching and lightning impulses flashover tests of strain insulator set artificially covered with snow were conducted in the Yonezawa testing station constructed in the northern part of Japan.
Withstand voltages of snow covered insulator set for high voltage AC transmission line have been investigated with the obtained test results.
The main points of the results are summarized as follows:
(1) The investigation of nature of snow on insulator sets shows that the specific gravity of snow is 0.3_??_0.4 and the conductivity of water melted from snow is maximum 40 μS/cm.
(2) Withstands voltages of insulator set covered with snow decreased as the specific gravity of snow increased.
(3) In the case of the specific gravity of 0.3_??_0.4, AC minimum withstand voltage per unit length was 74_??_79 kV/m.
(4) Switching impulse flashover voltage of snow covered insulator set with AC pre-stress was 10% lower than that without pre-stress. This is why snow condition is changed by leakage current under AC voltage application.
(5) It is clarified to make an insulation design for AC high voltage transmission line in heavy snow areas, on the basis of actual snow and meteorological conditions.

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In power system operation, it is necessary to consider both security and economy which are contradictory to each other. A very powerful means to satisfy this requirement is Optimal Power Flow (OFF). The Newton OFF with sparsity technique seems suited to on-line use from the viewpoint of computational speed. However, the method has several defects concerning convergence characteristics. This paper studies the following two problems to be overcome to use it in on-line tasks.
First, the P-Q decoupled OPF, which is usually faster than coupled one, does not converge in some systems. For such cases, we propose to introduce a decelerating factor to improve its convergence characteristics. Next, when many constraints are violated and enforced simultaneously, convergence tends to be difficult or the solution sometimes converges at a non-optimal point. Therefore, it is very important to identify binding inequalities effectively. In this paper, we propose an effective method of identifying binding inequalities based on the. Kuhn-Tucker condition. The validity of the proposed method is confirmed through numerical simulations on several test systems.

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In a molded-case circuit breaker (MCCB), an arc column is not always kept to burn inside deion plates but several times is shorten in the narrow area between electrodes. This unstable arc behavior causes several sudden drops in the arc voltage and suspension of the current limiting process. In this paper, an air-buffer chamber is proposed to be mounted in a MCCB to control the unstable arc motion and its effect on the current limiting performance of the MCCB is experimentally discussed.
It is found from the measurement of the attenuation of the projected 70GHz microwave that the temperature of the narrow area between electrodes begins to rise before the sudden drops in the arc voltage. This suggests us that the unstable arc motion is brought about with the high temperature air flow. Then, an air buffer chamber is mounted behind the arc chamber to efficiently exhaust the high temperature air as well as to hold the arc column inside the deion plates. The arcing time is reduced to 80% of that in the normal MCCB by mounting the air buffer cylinder of 20mm dia., 70mm length.

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The inter-anode arc caused by a Hall field is driven by a magnetic field into the anode-wall in an MHD generator, which limits the lifetime and performance of the generator.
The arc damage to inter-anode insulators of an MHD generator has been studied experimentally, in order to obtain basic data for the design of the inter-anode insulation. The experiment was conducted using a pair of electrodes with an insulator between them. Arc currents was supplied from a DC power source and magnetic field was applied perpendicular to the arc current. Experimental parameters are the insulator thickness, arc current, magnetic field and insulator materials. Quartz glass, boron nitride, magnesia, alumina, silicon carbide, silicon nitride etc. were tested and evaluated.
The following conclusions are evident from the experiments. Boron nitride and quartz glass are the most promising inter-anode insulators. Boron nitride has a higher arc voltage and longer cutting time than quartz glass, and it is the best material. Cutting time is approximately proportional to the -0.4th power of the magnetic field. Loss of insulator is approximately proportional to the 0.7th power of the arc current. The arc voltage increases linearly with the inter anode gap length. It also increases with magnetic field, but decreases with increase of arc current. An equation which approximates to such relations of arc voltage versus inter-anode gap length, arc current and magnetic field has been obtained. The standard deviation of the error of this equation is 12% for boron nitride and 15% for quartz glass.

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A belt-shaped damage. on an air electrode of phosphoric acid fuel cells is known to occur when air is introduced to fuel electrodes.
A theory for analyzing current density distribution, cell temperature distribution, and cell voltage distribution of the cell under air mixing condition in fuel electrode is presented.
In order to evaluate this analytical model, experiments are also carried out and compared with the theory.
An air introduced area is assumed to be a resistor having no electromotive force and its resistance are measured using a cell in which the air is supplied to both electrodes.
In proportion to the current through the cell, weight losses of the air electrode are observed at the same time.
When air is introduced to a portion of an operating fuel electrode, current density of the air introduced area decreased to negative values and that of the normal area increases. Cell temperature of the air introduced area also decreases and that of the normal area increases.
Cell voltage of the air introduced area also decreases considerably and that of the normal area decreases slightly.
Every these phenomena are quite similar to the calculated performance of the cell under air mixing condition in fuel electrode enough to justify the theory.

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