Effects of dimensionless numbers on decomposition of methane hydrate

It is necessary to elucidate the decomposition and combustion of methane hydrate for fire safety during transportation and storage to utilize it for commercial practice. The amount of methane evolved during the decomposition of methane hydrates is affected by the conditions such as the initial temperature, initial density and ambient temperature. In the present study, the internal temperature of methane hydrate and the amount of methane evolved during its decomposition were investigated by a dimensionless numerical analysis using a transient one-dimensional conduction model from a symmetrical methane hydrate ball heated by ambient air. The numerically calculated central temperature and the mass of evolved methane were compared with corresponding experimental results, and good agreement was obtained. The Damköhler and the Biot numbers were identified as two important dimensionless parameters during the decomposition of methane hydrate; the time histories of the central temperature, the mass of evolved methane and the reaction rates were numerically investigated by changing these dimensionless numbers. Consequently, the effects of dimensionless numbers on the decomposition of methane hydrate were elucidated

Die Biegeverformung der Kurbelwelle bei Schiffsdieselmotoren

Ein Verfahren zum Nachweis, daß innere Biegemomente in der Kurbelwelle vorkommen, ist die Messung des Formveränderungsgrades der Kurbelwangen. In dieser Arbeit wird darüber berichtet, welche Biegeverformungen der Kurbelwelle besonders wichtig und problematisch sind

Lowering of Electrostatic Actuator Driving Voltage and Increasing Generated Force Using Spontaneous Polarization of Ferroelectric Nematic Liquid Crystals

Abstract Although electrostatic actuators have a simple structure and are lightweight, their range of application is limited because a high applied voltage of more than several kilovolts is required for practical use. Since the force acting between the electrodes of an electrostatic actuator is determined by the electric charge accumulated at the electrode/dielectric interface, the focus is on spontaneous polarization of ferroelectrics to increase the charge. As the ferroelectric material, a nematic liquid crystal material with a spontaneous polarization of 5 µC cm−2 is used. It is demonstrated that a force of 1.3 N is generated at an applied electric field of 0.5 MV m−1. This force is 1200 times higher than that for standard paraelectric materials with a dielectric constant of ten. Further, the generated force responds linearly to the applied voltage, whereas it is proportional to the square of the applied voltage for paraelectric materials. The actuator function of this ferroelectric is examined using a double‐helical coil electrode fabricated using a 3D printer. It can be successfully operated at a voltage of several tens of volts. Under an electric field of 0.25 MV m−1, a remarkable contraction of 6.3 mm occurs, corresponding to 19% of the original length

Visceral pleural invasion is an invasive and aggressive indicator of non-small cell lung cancer

ObjectiveAlthough visceral pleural invasion by non-small cell lung cancer is considered a poor-prognostic factor, further information is lacking, especially in relation to other clinicopathologic prognostic factors. We assessed the relationship between visceral pleural invasion and other clinicopathologic characteristics and evaluated its significance as a prognostic factor.MethodsWe reviewed 1074 patients with surgically resected T1/2 non-small cell lung cancer for their clinicopathologic characteristics and prognoses. The patients were divided into 2 groups according to visceral pleural invasion status (visceral pleural invasion group and non-visceral pleural invasion group). Both groups were compared with regard to age, sex, histology, tumor size, tumor differentiation, lymph node involvement, lymphatic invasion, vascular invasion, scar grade, nuclear atypia, mitotic index, serum carcinoembryonic antigen level, and survival. Univariate and multivariate analyses were conducted.ResultsVisceral pleural invasion was identified in 288 (26.8%) of the resected specimens. Survival was 76.0% at 5 years and 53.2% at 10 years in the non-visceral pleural invasion group and was 49.8% at 5 years and 37.0% at 10 years in the visceral pleural invasion group. The difference between groups was highly significant (P < .0001). Visceral pleural invasion was also significantly associated with a higher frequency of lymph node involvement. However, regardless of N status (N0 or N1/2), there was a significant difference in survival when the visceral pleura was invaded. Visceral pleural invasion was observed significantly more frequently in tumors with factors indicative of tumor aggressiveness/invasiveness: moderate/poor differentiation, lymphatic invasion, vascular invasion, high scar grade, high nuclear atypia grade, high mitotic index, and high serum carcinoembryonic antigen level. By multivariate analysis, visceral pleural invasion proved to be a significant independent predictor of poor prognosis in non-small-cell lung cancer patients with or without lymph node involvement.ConclusionsVisceral pleural invasion is a significant poor-prognostic factor, regardless of N status. Our analyses indicated that visceral pleural invasion is an independent indicator of non-small cell lung cancer invasiveness and aggressiveness