Estimation of Normalized Eigenmodes and Natural Frequencies by Using the Effect of Accelerometers Mass

Several studies have been attempted to grasp the modal characteristics in machine operation. Derivation of the scaling factor for normalized eigenmodes is one of the important issues in operational modal analysis. In this study, we propose a procedure with the mass of piezoelectric acceleration transducers. Then the vibration testing for the mass change method is performed without using additional masses. We obtain the modal characteristics from the acquired acceleration responses by the transducers that is less than all measurement points. That is, the measurement is performed multiple times by changing the measurement locations. A modified procedure is proposed to calculate the scaling factor for normalized eigenmodes and proper natural frequencies by removing the influence of the mass of the added piezoelectric accelerometer. The validity of the proposed method is verified by numerical calculations and experiments of a rectangular plate

テンネン センイ デ キョウカ シタ キノウセイ グリーン コンポジット ノ カイハツ

Various types of unidirectional and random bamboo fiber reinforced “green” composites were fabricated, and examined their damping properties as a function of fiber content. The loss factors decreased with increasing fiber content. However they decreased gently higher than 40mass percent fiber content, the tensile modulus increased proportionally to the fiber content of about 80mass percent. The definite relationship between loss factor and Young’s modulus was not found. In addition, loss factors of random fiber (10mm fiber) reinforced “green” composites are larger than loss those unidirectional (continuous fiber) ones

Prevalence and Outcomes of Acute Hepatitis B in Okayama, Japan, 2006-2010

Hepatitis B virus (HBV) is one of the major viruses causing acute hepatitis. Recently, the incidence of acute hepatitis with genotype A has been increasing in Japan. The aim of this study was to investigate acute hepatitis B (AHB) in Okayama prefecture, with special attention to HBV genotype A. AHB patients who visited one of 12 general hospitals in Okayama prefecture between 2006 and 2010 were retrospectively analyzed. Over the course of the study period, 128 patients were diagnosed with AHB. Sexual transmission was supposed in the majority of patients (78 patients, 61%), including 59 (76%) having sex with heterosexual partners. The genotypes of HBV were assessed in 90 patients (70%), of whom 27 patients were infected with genotype A, 5 with genotype B, and 58 with genotype C. The prevalence of genotype A was significantly higher among male patients (28.7%), aged 20-29 (35.6%, p＜0.01), among men who had sex with men (100%, p＜0.005), and among patients having sex with unspecified partners (44.8%, p＜0.005). Genotype A was not a significant factor associated with delayed HBsAg disappearance. Caution should be exercised with regard to sexually transmissible diseases in order to slow the pandemic spread of AHB due to genotype A

Recent Results from LHD Experiment with Emphasis on Relation to Theory from Experimentalist’s View

he Large Helical Device (LHD) has been extending an operational regime of net-current free plasmas towardsthe fusion relevant condition with taking advantage of a net current-free heliotron concept and employing a superconducting coil system. Heating capability has exceeded 10 MW and the central ion and electron temperatureshave reached 7 and 10 keV, respectively. The maximum value of β and pulse length have been extended to 3.2% and 150 s, respectively. Many encouraging physical findings have been obtained. Topics from recent experiments, which should be emphasized from the aspect of theoretical approaches, are reviewed. Those are (1) Prominent features in the inward shifted configuration, i.e., mitigation of an ideal interchange mode in the configuration with magnetic hill, and confinement improvement due to suppression of both anomalous and neoclassical transport, (2) Demonstration ofbifurcation of radial electric field and associated formation of an internal transport barrier, and (3) Dynamics of magnetic islands and clarification of the role of separatrix