Construction of Lyapunov function for power system based on solving linear matrix inequality

This paper presents construction of Lyapunov functions for power systems based on solving the Linear Matrix Inequality (LMI) derived from the Lyapunov stability theorem considering the dynamics of load characteristic and AVR control system. The proposed Lyapunov function is constructed as a quadratic form of state variables and an integral term which satisfies the curl equation and the sector condition. An induction machine and a synchronous machine are considered as load characteristics. One‐machine one‐load infinite bus system is considered taking into account the flux decay effects and AVR with one time constant of the generator. To verify the proposed Lyapunov function, the transient stability assessment is shown. The critical clearing times given by the proposed Lyapunov function are compared with those obtained by the numerical integration method, and they are shown to be practical. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 158(4): 42– 50, 2007; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20328     

Contextual cropping and scaling of TV productions

In this paper, an application is presented which automatically adapts SDTV (Standard Definition Television) sports productions to smaller displays through intelligent cropping and scaling. It crops regions of interest of sports productions based on a smart combination of production metadata and systematic video analysis methods. This approach allows a context-based composition of cropped images. It provides a differentiation between the original SD version of the production and the processed one adapted to the requirements for mobile TV. The system has been comprehensively evaluated by comparing the outcome of the proposed method with manually and statically cropped versions, as well as with non-cropped versions. Envisaged is the integration of the tool in post-production and live workflows.     

In vitro and in vivo antioxidant properties of ferulic acid: A comparative study with other natural oxidation inhibitors

Ferulic acid exhibits a wide range of therapeutic effects that are attributed to its potent antioxidant capacity. However, in vitro antioxidant properties of ferulic acid have not been elucidated in detail. Evidence that polyphenols, including ferulic acid, act as antioxidants in vivo is also limited. In order to elucidate in more detail the scientific background of antioxidant activities of ferulic acid, we carried out in vitro and in vivo experiments. We focused on superoxide anion scavenging activity, xanthine oxidase inhibition activity, and chain-breaking activity. The combined antioxidant activity from radical scavenging and xanthine oxidase inhibition of ferulic acid was much weaker than that of (−)-epigallocatechin gallate (EGCG) and ascorbic acid. On the other hand, EGCG, ascorbic acid and ferulic acid exhibited chain-breaking activity and prevented ischaemia-reperfusion-associated intestinal injury. Chain-breaking activity may play a contributory role in the protective effect of ferulic acid on oxidative injury in humans and in in vivo studies.     

Emergency TeleOrthPaedics m-health system for wireless communication links

For the first time, a complete wireless and mobile emergency TeleOrthoPaedics system with field trials and expert opinion is presented. The system enables doctors in a remote area to obtain a second opinion from doctors in the hospital using secured wireless telecommunication networks. Doctors can exchange securely medical images and video as well as other important data, and thus perform remote consultations, fast and accurately using a user friendly interface, via a reliable and secure telemedicine system of low cost. The quality of the transmitted compressed (JPEG2000) images was measured using different metrics and doctors opinions. The results have shown that all metrics were within acceptable limits. The performance of the system was evaluated successfully under different wireless communication links based on real data.     

Development of a high efficiency refrigeration compressor

In order to improve the energy efficiency ratio of small reciprocating hermetic compressors the following factors are investigated: clearance volume, bore and stroke, rod length ratio, geometric dimensions of a piston and valves and superheat of suction gas.A prototype machine is developed based on this investigation. The reliability of this new type of compressor is confirmed and its energy efficiency ratio reaches 3.02 J W⁻¹ s⁻¹, which is 25% higher than the average value of our current machines.     

High-temperature phase relations in the ternary Ga-Mn-Ni system

Isothermal sections of the ternary Ga-Mn-Ni phase diagram at 800 and 1000 °C have been investigated for alloys with a manganese content below 70 at.% for 800 °C and a content below 65 at.% at 1000 °C. The high-temperature phase relations among the solid phases have been analyzed with diffusion couples and by energy dispersion x-ray spectroscopy (EDX) on quenched two-phase alloys. For these temperatures, the solidus line was determined from quenched alloys from the solid and liquid two-phase region by EDX analysis and the liquidus line by an overall evaluation of the phases found in the quenched alloys. By powder x-ray diffraction (XRD) measurements, the results for the equilibria among the solid phases were confirmed and the lattice parameters for the martensite formed from the β phase have been determined over a wide range of compositions.     

Production of low electron temperature ECR plasma for plasma processing

Low-electron-temperature ECR plasma with high electron density was realized under the mirror magnetic field configuration in the H₂ and the Ar/N₂ plasma. Especially, the electron temperature was observed to be less than 2 eV in the Ar/N₂ plasma. It was found from the calculation of particle and power balance in steady state that the decrease in the electron temperature observed in the Ar/N₂ plasma was due to the effect of the magnetic-mirror confinement of the N₂ plasma. Furthermore, our calculated results suggest that the effect of magnetic-mirror on the decrease in the electron temperature depends on the collisional cross section between electrons and neutral particles.     

Phase equilibrium and minor-element distribution between Ni3S2-FeS matte and calcium ferrite slag under high partial pressures of SO2

Calcium ferrite slag has been successfully used in the copper smelting process, but no attempt has been made to use it in the nickel smelting process. The phase equilibrium and the distribution of minor elements between the Ni₃S₂-FeS matte and the CaO-FeO_x-based slag (containing about 2 wt pct MgO) in a magnesia crucible were investigated at 1523 K under controlled partial pressures of S₂, O₂, and SO₂ of 10.1, 50.7, and 101.3 kPa, respectively. The results were compared with those for the iron-silicate-based slag, and the following conclusions were obtained: (1) there is no significant difference in the solubility of nickel between both slags in the high-matte-grade range, (2) the dissolution of cobalt in the calcium ferrite slag is clearly smaller than that in the iron silicate slag, (3) detrimental arsenic, antimony, and bismuth are preferentially collected and fixed in the calcium ferrite slag rather than in the iron silicate slag, and (4) it is considered, with regard to technical feasibility, that the use of the calcium ferrite slag in a converting process of the Bessemer matte will have a prominent future for the nickel converting stage.     

Pulmonary artery hypertension in methylmalonic acidemia

Methylmalonic acidemia (MMA) is an autosomal recessive disorder that can be classified into two types: (1) vitamin B12‐responsive and (2) vitamin B12‐non‐responsive. In MMA cases with long‐term survival, renal failure is often a problem, and timing for kidney transplantation for MMA is controversial. We encountered a vitamin B12‐non‐responsive MMA case for which regular hemodialysis for renal failure was initiated; the patient was 16 years old when she first received regular hemodialysis and 35 years old when she developed pulmonary artery hypertension (PAH). PAH can complicate regular hemodialysis; however, PAH in this case was considered to be a complication of MMA because it was responsive to medical treatment and reversible. In this report, we discuss the role of regular hemodialysis in MMA and the causal relationship between MMA and regular hemodialysis for PAH.     

Impact of Chronic Hepatitis C Virus Genotype 1b Infection on Triglyceride Concentration in Serum Lipoprotein Fractions

Reduced low-density lipoprotein (LDL) cholesterol level is a characteristic feature of dyslipidemia in chronic hepatitis C virus (HCV) infection. However, abnormality in serum triglyceride (TG) has not been fully investigated. To clarify the impact of HCV genotype 1b (G1b) infection and advanced fibrosis on serum TG profiles, TG concentrations in lipoprotein fractions were examined in fasting sera from 185 subjects with active or cleared HCV infection by high-performance liquid chromatography. Serum lipoproteins were fractionated into four classes: chylomicron, very low-density lipoprotein (VLDL), LDL, and high-density lipoprotein (HDL). Then, the significance of HCV G1b infection on TG levels in each lipoprotein fraction was determined using multiple regression models. We found that active HCV G1b infection was positively associated with high HDL-TG levels and low VLDL-TG levels, independent of other factors included in the regression model. In VLDL sub-fractions, active HCV infection was only found to be associated with low levels of large VLDL-TG. Similarly, advanced liver fibrosis in chronic HCV G1b infection was associated with high levels of LDL-TG, HDL-TG, and small VLDL-TG, independent of other clinical factors. These findings indicate that active HCV G1b infection and advanced fibrosis are closely associated with abnormal serum TG profiles.