Output Power Smoothing and Hydrogen Production by Using Variable Speed Wind Generators

This paper presents a combination system of wind energy conversion and hydrogen production. Hydrogen is expected as an alternative energy source in the future, and this is the best way to produce it from renewable energy like wind energy. On the other hand, the output of a wind generator, in general, fluctuates greatly due to wind speed variations, and thus the output fluctuations can have a serious influence on the power system operation. In the proposed system, a variable speed wind generator is adopted, and an electrolyzer is installed in parallel with it for hydrogen production. Output power from the wind generator is smoothed and supplied to the power system as well as to the electrolyzer based on the cooperative control method. The performance of the proposed system is evaluated by simulation analyses, in which simulations are performed by using PSCAD/EMTDC.      

Temperature dependence of the yield strain of a Zr-based metallic glass at the glassy state

In the glassy temperature region from the ambient to glass transition temperature, an apparent Young's modulus (E_ap), the slope of the initial linear part on the stress–strain curve, in a Zr-based metallic glass clearly depends on both temperature and strain rate, indicating that viscous contribution is included in the elastic response. Because the yield stress depends on temperature and strain rate as the same manner with E_ap, the yield strain was found to keep the “universal” critical strain 0.020 for many metallic glasses at the ambient temperature. This suggests that the yield phenomenon is simply dominated by E_ap.     

Direct production of Nb3Al superconducting coil by electron beam irradiation on a cold-sprayed cylinder

The direct production of Nb₃Al superconducting coils using the combinational technology of ‘cold spray’ as physical deposition and ‘electron beam’ as surface modification has been proposed. Using this method, the helical line of the Nb₃Al superconductor is produced directly on a cylinder without conventional wiring process. In order to prove the possibility of direct coil production, we first made flat-plate and cylindrical samples, and then examined the characteristics as superconductor. The flat-plate samples showed the phase transition in magnetization and the characteristics of superconductivity when the output powers of the electron beam were over 800 W at a beam speed of 3 m/s and 1200 W for 6 m/s. It was confirmed that a 10-turn single-layer coil with a ?40 mm diameter and a length of 50 mm generated a magnetic field of 2.7 mT at 20.5 A.     

An augmented automatic choosing control of observer type for nonlinear systems with linear measurement and its application to power systems

This paper deals with a feedback control using automatic choosing functions and the observer-control design procedure for nonlinear systems with linear measurement. A constant term which arises from linearization of a nonlinear equation is treated as a coefficient of a stable zero dynamics. A given nonlinear system is linearized piecewise so as to be able to design the linear optimal controllers with the linear observers. By the automatic choosing functions, these controllers are smoothly united into a single nonlinear feedback controller, which is called an augmented automatic choosing control of observer type. This controller is applied to a transient stability of power systems, whose simulation results show that the new controller enables to expand the stable region well. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Intraoperative magnetic tracker calibration using a magneto-optic hybrid tracker for 3-D ultrasound-based navigation in laparoscopic surgery

This paper describes a ultrasound (3-D US) system that aims to achieve augmented reality (AR) visualization during laparoscopic surgery, especially for the liver. To acquire 3-D US data of the liver, the tip of a laparoscopic ultrasound probe is tracked inside the abdominal cavity using a magnetic tracker. The accuracy of magnetic trackers, however, is greatly affected by magnetic field distortion that results from the close proximity of metal objects and electronic equipment, which is usually unavoidable in the operating room. In this paper, we describe a calibration method for intraoperative magnetic distortion that can be applied to laparoscopic 3-D US data acquisition; we evaluate the accuracy and feasibility of the method by in vitro and in vivo experiments. Although calibration data can be acquired freehand using a magneto-optic hybrid tracker, there are two problems associated with this method--error caused by the time delay between measurements of the optical and magnetic trackers, and instability of the calibration accuracy that results from the uniformity and density of calibration data. A temporal calibration procedure is developed to estimate the time delay, which is then integrated into the calibration, and a distortion model is formulated by zeroth-degree to fourth-degree polynomial fitting to the calibration data. In the in vivo experiment using a pig, the positional error caused by magnetic distortion was reduced from 44.1 to 2.9 mm. The standard deviation of corrected target positions was less than 1.0 mm. Freehand acquisition of calibration data was performed smoothly using a magneto-optic hybrid sampling tool through a trocar under guidance by realtime 3-D monitoring of the tool trajectory; data acquisition time was less than 2 min. The present study suggests that our proposed method could correct for magnetic field distortion inside the patient's abdomen during a laparoscopic procedure within a clinically permissible period of time, as well as enabling an accurate 3-D US reconstruction to be obtained that can be superimposed onto live endoscopic images.     

Analytical method for carbamate pesticides in processed foods by LC/MS/MS

A rapid analytical method for the simultaneous determination of carbamate pesticides in processed foods was established by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). The pesticides were extracted from samples with acetonitrile using accelerated solvent extract equipment, except for the fine powder type spices, which were extracted in an ultrasonic bath. The crude extract was cleaned up with a multi-solvent GPC column (Shodex Asahipak GF-310 HQ) using acetonitrile as a mobile phase. The eluent from the column at the retention time between 13 to 18 min was concentrated under nitrogen gas and dissolved in a mixture of acetonitrile-water-0.2 mol/L ammonium formate buffer pH 6.0 (10 : 9 : 1). An aliquot was injected into the LC/MS/MS using electrospray ionization (ESI) with acquisition in the positive mode.The recoveries of 29 kinds of pesticide from dried fruits (raisin, prune and mango) and spices (turmeric, masala, sage, thyme and red pepper) fortified at levels of 0.1 and 0.01 microg/g were mostly in the range of 50 to 150% and those from soybean paste and soy sauce fortified at 0.01 microg/g were 46.9 to 122.6% (C.V. 3.8 to 37.6%), except for 4 kinds of pesticide. The determination limits (S/N> or =10) corresponded to 0.001 to 0.05 mug/g of the pesticides in red pepper.     

Simultaneous determination of veterinary drugs in livestock foods and seafoods using liquid chromatography/tandem mass spectrometry

A simultaneous determination of veterinary drugs in livestock food and seafood using liquid chromatography with tandem mass spectrometry (LC/MS/MS) was developed. Veterinary drugs were extracted with 95% acetonitrile. The solution was passed through a Florisil column, and the solvent was replaced with phosphate buffer. The extract was charged on a Sep-Pak Plus C(18) mini-column and divided into 40% methanol eluate fraction and 70% acetonitrile eluate fraction. Test solutions were analyzed by LC/MS/MS with gradient elution. By using this method, 37 kinds of veterinary drugs were obtained with over 60% recovery, and quantitation was possible in cattle muscle, egg and fish. This method was inapplicable to 28 kinds of veterinary drugs. Although quantitation was not achieved, 42 other kinds of veterinary drugs can be screened. Since the limit of quantitation for this method is less than the provisional limit in general, it is useful as a screening method in residual analysis of veterinary drugs.     

Survey of pesticide residues in imported cereal products (1994.4 approximately 2006.3)

A survey of pesticide residues in 490 imported cereal products on the Tokyo market from April 1994 to March 2006 was carried out. Eight kinds of organophosphorus pesticides (chlorpyrifos, chlorpyrifos-methyl, DDVP, diazinon, etrimfos, malathion, MEP and pirimiphos-methyl) were detected at levels between Tr (below 0.01 ppm) and 0.82 ppm from 91 samples.In our investigations, chlorpyrifos-methyl and malathion tended to be detected in samples from America, pirimiphos-methyl in those from Europe, and MEP in those from Oceania. Thus, pesticide residues seemed to be different in produce from different areas.Residue levels of these pesticides were calculated as between 0.08 and 13.2% of their ADI values according to the daily intake of cereal products. Therefore, these cereal products should be safe for normal usage.     

Effect of addition of Tween 80 and potassium dihydrogenphosphate to basal medium on the isolation of marine eukaryotes, thraustochytrids

Tween 80, KH(2)PO(4) and tomato juice were added to basal medium for the isolation of thraustochytrids. By the addition of Tween 80 and KH(2)PO(4), the number of thraustochytrids isolated from seawater increased. KH(2)PO(4) and Tween 80 were considered to be useful for isolating thraustochytrids.     

Synthesis of Al2O3 coatings on Ti(C,N)-based cermets by microwave plasma CVD using Al(acac)3

Aluminum acetylacetonate (Al(acac)₃) was used as a precursor to synthesize aluminum oxide (Al₂O₃) coatings on Ti(C, N)-based ceramic by microwave plasma CVD (MPCVD). Al₂O₃ coatings transformed from γ phase to δ phase and α phase and as microwave power (p_M) and total pressure (P_tot) increased. The effects of p_M and P_tot on the microstructure of the Al₂O₃ coating and oxidation of the substrate have been investigated. The relationship between phase structure and adhesive strength of the coatings was also studied. Coatings deposited at p_M = 1.0-1.2 kW and P_tot = 400 Pa exhibited good adhesion strength (Class 1).