Macroscopic estimation method of the mixedness of Kenics type static mixer

We investigated the mixing process of the Kenics type static mixer, in which the mixing is enhanced by both advective mixing and mixing due to molecular diffusion in order to propose an estimation method of the mixedness. The results show that the element divides, folds and stretches the mixing fluids and forms a lamellar structure with striation width l _a . The value of l _a decreases with an increase in the number of elements by l _a -(2 ⁿ⁻¹)⁻¹, which represents the characteristics length of advective mixing. The characteristic length of mixing due to molecular diffusion l _d can be estimated by solving the one-dimensional unsteady species conservation equation analytically. The macroscopic estimation and prediction method of mixedness is proposed as function of l _a and l _d . When l _a >l _d , the advective mixing is dominant, while, when l _a <l _d , the mixing due to molecular diffusion plays an important role.     

Crystal growth and optical properties of the Nd doped LuF3 single crystals

Thirty millimeter diameter single crystal of Nd³⁺ doped LuF₃ was grown using LiF as solvent. The single phase crystallization was confirmed by the powder X-ray diffraction, and high structural perfection was demonstrated by X-ray rocking curve (XRC) measurements. FWHM of XRC for 220 reflection was 32 arcsec. No remarkable absorption due to unfavorable impurities was observed from optical absorption measurements in the VUV spectral region. The crystal showed the VUV luminescence peaking around 178 nm that is consistent with the 4f²5d-4f³ transition of Nd³⁺ ion. The luminescence intensity of Nd:LuF₃ under X-ray irradiation was significantly higher than that of reported VUV scintillators such as Nd:LaF₃ or Nd:LiLuF₄.     

Amino acid components of lees in salmon fish sauce are tyrosine and phenylalanine

We report that the lees in salmon fish sauce consist of Tyr and Phe. The concentration of free l-Tyr (2.0 mM) was almost same as the saturated concentration (2.4 mM) in water at 20°C. This result shows that lees are formed by Tyr precipitation due to its saturation in the sauce.     

A new variable‐speed,constant‐frequency,stand‐alone power generating system

Variable‐speed and constant‐frequency power generating systems using rotor excitation of the wound‐rotor induction machines have been used for such applications as variable‐speed pump generators and flywheel energy storage systems. However, the stand‐alone generating system of this type has only been reported and has not yet been practically used. On the other hand, the stand‐alone generating systems using diesel engines have been widely used for emergency supplies of plants or isolated islands and so on. However, in these cases, synchronous generators are usually used. If the output frequency is to be kept constant, there is the need to control the speed of the engine using a high‐performance governor. Even then, the output frequency changes in the case of a sudden load change. This paper proposes a new stand‐alone power generating system. In this system, the constant‐frequency output voltage can be obtained even though rotor speed changes by several percent. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(2): 75–85, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10191     

High-frequency power transmission and selective distribution among loads by using distributed constant lines

A widely used high-frequency induction heating system usually consists of a high-frequency power source and a load circuit to be heated. Since such a system can heat only one load circuit, heating two or more loads requires that other sytems be devised. Several problems result, including the need for many power sources, switches, and high-frequency power transmission lines. To solve these problems, the authors propose a new system that can selectively supply two induction heating circuits with high-frequency power. This system is composed of a high-frequency voltage-type inverter, a parallel resonant load circuit, and a series resonant load circuit, which are connected in series by distributed constant lines of specific length. Analysis of the operating characteristics of the system confirms that the system can supply the loads with high-frequency power selectively and efficiently, with minimum interference between loads. The authors have compared theoretical simulation waveforms with actual waveforms observed on experimental equipment with output ratings of 1 to 2 MHz and 1 kW. As a result, experimental data agree well with theoretical data. This paper describes an operating principle and operating conditions of the system, and verifies that the theory we discuss is reasonable.     

A novel strategy for a high‐power utility interactive inverter with a series active filter

High‐power utility interactive inverters used for large‐capacity energy storage systems are composed of multiple connected inverters, in order to realize high efficiency and high performance of the harmonic elimination characteristic simultaneously. Some disadvantages of multiple connected inverters, such as harmonic current flowing from an inverter unit to the other one, and increase of the number of inverter units, cannot be overcome easily. This paper presents a novel strategy for a high‐power utility interactive inverter, which is composed of a large power with low‐switching‐frequency PWM inverter (high‐power PWM inverter), an LC passive filter, and a series active filter (series AF). Because harmonic components contained in the utility line current are absorbed by the series AF, the switching frequency of the PWM inverter can be selected to about 1 kHz. In addition because the power capacity and the output voltage of the series AF can be suppressed lower than 10% of the power capacity and the output voltage of PWM inverter, low‐voltage and high‐speed power devices can be applied to the series AF. Consequently, high power, high efficiency, and high harmonics elimination performance can be realized without increasing the number of inverter units. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(2): 57–66, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10048     

Comparisons of Point Estimation Methods in the 2-parameter Weibull Distribution

The following 3 estimation methods in a Weibull distribution are well-known; Maximum Likelihood Estimation (MLE), Coefficient of Variation (CV), and Weibull Probability Paper (WPP). By simulation we conclude that the WPP method is best.     

Viscoelasticity of some engineering plastics analyzed with the modified stress-optical rule

The complex Young's modulus, E*(ω), and the complex strain-optical coefficient, O*(ω), of poly(ether sulfone) (PES), polysulfone (PSF), and polyethermide (PEI), were measured over the frequency range 1 to 130 Hz. The data were analyzed with a modified stress-optical rule: The Young's modulus was decomposed into two complex functions, E(ω) and E(ω); the modified stress-optical coefficient, C_R and C_G, associated with the rubber (R) and glass (G) components, respectively, were determined. The results for six polymers, including polystyrene, poly(α-methyl styrene), and bisphenol A polycarbonate were compared with each other. One of the coefficients, C_R, equivalent to the stress-optical coefficient in melts, mainly depended on the way in which phenyl groups were connected to the chain. The other, C_G, was in the range of 20 to 40 Brewsters, and did not strongly depend on the details of polymer structure. The component function, E(ω), which was located in the glassy region and originated from the high glassy modulus, was almost the same in shape when plotted against ω with double logarithmic scales. The R component, E(ω), located at the long time end of the glass-to-rubber transition zone, was slightly sensitive to the molecular structure of polymers.