Combined system of a series active filter and a shunt passive filter—an optimum design of the shunt passive filter

The combined system of a series active filter and a shunt passive filter that is proposed by the authors has the ability to eliminate a major disadvantage of shunt passive filters, namely, harmonic amplification. The series active filter needs a much smaller kVA rating than a conventional shunt active filter, and as a result, the combined system has good filtering characteristics and high efficiency. This paper presents an optimum design of the shunt passive filter that makes possible a great reduction in the required kVA rating of the series active filter. It can minimize the peak voltage across the series active filter and reduce the required kVA rating of the filter to 60 percent. A computer simulation geared to practical applications of large three-phase. twelve-pulse thyristor rectifiers is used to compare the compensation characteristics of the optimized system with those of a combined system that uses a conventional shunt passive filter. Experimental results obtained with a laboratory model of the filter corroborate the design approach.     

Highly selective partial hydrogenation of 1,3-butadiene on platinized-platinum electrode in ethylenediamine at open circuit

It was found that platinized-platinum ethylenediamine (EDA) is extremely selective (ca 93%) for the partial hydrogenation of 1,3-butadiene, given three isomeric butenes in a ratio of 1-butene: trans-2-butene: cis-2-butene = 13.2:2.5:1. Such a highly selective partial hydrogenation would be due to a specific adsorption of EDA on pt-Pt giving rise to the replacement of the adsorbed butenes which were formed from the partial hydrogenation of 1,3-butadiene.     

Surface condition of Si implanted GaAs revealed by the noncontact laser/microwave method

The surface recombination of GaAs which has a heavily doped surface layer formed by Si implantation and subsequent annealing has been investigated using the noncontact laser/microwave evaluation method. The experimental results of the samples implanted with doses ranging from 1.0 × 10¹¹ to 3.9 × 10¹² cm⁻² at an energy of 100 keV indicate that the effective surface recombination velocity decreases with dosage because of the heavily doped layer formed after the annealing. On the other hand, the results of the samples implanted with a dose of 3.9 × 10¹² cnr⁻² at energies raging from 50 to 180 keV indicate that the effective surface recombination velocity increases with energy. This is mainly due to the decrease in the peak carrier concentration in the heavily doped layer.     

Indirect Measurement of Instantaneous Arterial Blood Pressure in the Human Finger by the Vascular Unloading Technique

For the indirect measurement of beat-to-beat systolic and diastolic pressure in the human finger, a new hydraulic servocontrol system was designed to maintain the vascular volume in the unloaded state. The servocontrol system consists of a compression chamber equipped with an occluding cuff and a photoelectric plethysmograph, an electromagnetic shaker, and a volume servo circuit. The shaker connected to a diaphragm actuator is used for controlling the cuff pressure. The vascular volume change in the finger is detected by the photoelectric plethysmograph. The plethysmographic signal is fed into the servo circuit to control the cuff pressure, which is clamped at a proper value corresponding to the unloaded vascular volume. At this state the controlled cuff pressure follows the intraarterial pressure. The accuracy of this method was evaluated using an in vitro vascular model of the finger. Comparisons with direct measurement were carried out successfully in four normotensive and six hypertensive subjects.     

Reduction characteristics of Fe-Bi-P mixed oxide catalysts and their ammoxidation activities of propylene

The characteristics of Fe-Bi-P mixed oxide catalysts of different compositions for reduction by propylene or ammonia and the ammoxidation activities of propylene were studied using a McBain type thermobalance and the pulse reaction technique respectively. By comparing the dependency of the reduction characteristics and catalytic activity with oxide composition and also the reduction rates and reoxidation rates of the reduced catalyst it was concluded that the ammoxidation of propylene on Fe-Bi-P mixed oxide catalyst proceeds through alternate repetition of reduction by propylene and reoxidation by oxygen, and that abstraction of allylic hydrogen from adsorbed C₃H₆ is the rate determining step.     

Remote Interaction between Human and Humanoid Robot

The last few years have been characterized by the continuous development of information and communication technologies, robotics technologies, and home automation technologies. The number of application areas for such technologies is increasing, especially in fields rather outside the pure industrial scenario, often identified as service applications. These are healthcare, public service provisions, social services for disadvantaged citizens, technical aids for promoting the independence of disabled and elderly people, and many others.With this joint research Scuola Superiore Sant'Anna and Waseda University, starting from the current availability of several mechatronic prototypes in their research laboratories, intend to validate different telecommunication tools for the remote control of mechatronic systems by demonstrating the feasibility and potential benefits deriving from the integration of such technologies.     

Analysis of size distributions of primary oxide inclusions in Fe-10 mass Pct Ni-M (M=Si, Ti, Al, Zr, and Ce) alloy

The planar and spatial size distributions of primary oxide inclusions were measured in an Fe-10 mass pct Ni alloy on deoxidation with 0.2 mass pct M (M=Si, Ti, Al, Zr, and Ce). It was found that the size distribution of inclusions obtained at a certain magnification in microanalysis was accurate only in a limited range of particle size, due to the limit of observation for the minimum size and observed area. The inclusion characteristics such as mean spatial diameter, , the number of particles per unit volume, N _v, and the volume fraction of particles, f _v, were estimated from the size distribution obtained in a planar cross section by using different methods. The and N _v values and the size distribution estimated from the cross-sectional method using different magnifications were compared with those obtained from the extraction method. The f _v values obtained from size distribution were found to be considerably greater than those from chemical analysis of oxygen or metal element as inclusion. Furthermore, the behavior of the size distribution as a function of holding time at 1873 K is discussed.     

Preparation of nickel and Ni-Zn ferrite films by thermal decomposition of metal acetylacetonates

Nickel and Ni-Zn ferrite (Ni_1–x Zn _x Fe₂O₄) films were prepared on various substrates (quartz glass, MgO single crystal, etc.) by thermal decomposition of metal acetylacetonates (Ni (acac)₂ · 2H₂O, Zn (acac)₂ · 2H₂O and Fe (acac)₃). Typical decomposition and heat treatment conditions for obtaining a single phase of NiFe₂O₄ film were as follows: evaporation temperature of Ni-Fe complexes: 230°C, the mole concentration of Fe (acac)₃,R (%) = Fe (acac)₃/(Fe (acac)₃ + Ni (acac)₂ · 2H₂O) = 33, substrate temperature: 330 to 550° C, and heat treatment of the as-grown film: 800 to 1000° C, 1 h. Ni_1–x Zn _x Fe₂O₄ films were obtained by controlling the compositionR in Ni-Fe complexes and the evaporation temperature of Zn (acac)₂ · 2H₂O. The Ni-Zn ferrite film at the compositionx = 0.37 (Ni_0.63Zn_0.37Fe₂O₄) gave the maximum saturation magnetization _s = 60 emu g^–1 and the coercive forceHc 25 Oe. These films showed a magnetic anisotropy which makes the magnetization easy parallel to film surface.     

Nondestructive identification of isotopes using nuclear resonance fluorescence

Nondestructive identification of heavy isotopes concealed in a thick iron box has been demonstrated by using nuclear resonance fluorescence. A quasi-monochromatic photon beam produced by the collision of laser quanta with high energy electrons was used for resonant excitation of nuclear levels in (206)Pb and (208)Pb. By measuring the resonant γ rays emitted from (206)Pb and (208)Pb, each of these isotopes were clearly identified. The ratio of the effective thickness, i.e., concentration distribution, of these isotopes was deduced from the relative intensities of the measured nuclear resonance fluorescence strengths.