Fracture Criterion for Alumina Ceramics Subjected to Triaxial Stresses

Triaxial stress tests of alumina ceramics were conducted by pure bending under hydrostatic pressure, and by internal pressurization of an open-end thin-walled tube under hydrostatic pressure. The fracture stresses plotted in the principal stress space did not conform to existing fracture criteria. So, for fracture of the material, the flaw model consisting of randomly oriented penny-shaped cracks was assumed. The fracture criterion obtained from a statistical viewpoint by taking account of flaw distributions could explain well the experimental results.     

Phase Equilibrium in the System PbO-TiO2–ZrO2

Phase equilibrium relations in the system PbO–TiO₂–ZrO₂ were studied by quenching in the range where the PbO content is 50 mole % and more. Isotherms were examined at 1100°, 1200°, and 1300°C and tie lines were determined between the liquid and solid solution in equilibrium. The incongruent melting point of PbZrO₃ was 1570°C and the equilibrium between liquid, PbO-type solid, and PbZrO₃ is peritectic. Pb(Zr,Ti)O₃ solid solutions containing more than 14 mole % PbZrO₃ decomposed to liquid, ZrO₂, and Pb(Zr,Ti)O₃ and the decomposition temperature rises from 1340° to 1570°C with increasing PbZrO₃ content. The system PbTiO₃–PbZrO₃ should not be treated as a binary, but as a section of the ternary system.     

Effects of Environment on Friction and Wear of Al-Si Alloy Impregnated Graphite Composite

Pin-on-disk-type wear experiments for an Al-Si alloy impregnated graphite composite (pin) in contact with a bearing steel (disk) were conducted at 100N normal load (100 Newtons) in air, argon, and deionized water to investigate the effects of environment on the tribological characteristics of the composite. The friction and wear behavior and the pin-lifting phenomenon due to wear particle ingress into the contact surfaces were continuously measured during the experiments. At low relative humidity (RH) levels, the friction coefficients in air and argon are high (0.32 to 0.39) and decrease with increasing RH to values around 0.2. The friction coefficients in air have reached a minimum of 0.15 to 0.17 between 50 and 70% RH and increased slightly at 80% RH. The friction coefficients in argon are constant at about 0.2 between 10 and 80% RH. Because of the lubricating action of a water film, the friction coefficient in deionized water is slightly lower (0.1 to 0.17) than that in air. The mean wear rate of 10^?4 to 8 × 10^?4 mm ³ /mm (specific wear rate; w _s = 10 ^?6 to 8 × 10^{? 6} mm ² /N) is very high in a severe wear regime at RH levels lower than 10% in air, decreases with increasing RH to a minimum in the middle RH range (30 to 60%), and increases slightly at RH levels higher than 70%. Although the mean contact pressure is very high (31.8 MPa), mild wear with the rates of 10^?8 to 10^?7 mm ³ /mm (w _s = 10^?10 to 10^?9 mm ² /N) occurs in the middle RH range. The same change in wear with RH as that in air is found in argon but the wear rate in argon is slightly lower than the wear rate in air. The height of the pin-lifting, having a wear reduction effect, is greater in argon than in air over almost the whole RH range. The wear rate in deionized water is nearly equal to the rate at 70% RH in air and argon.     

Development of Hybrid Solar Systems Using Solar Thermal,Photovoltaics, and Wind Energy Translation from “Journal of the Japanese Solar Energy Society,” Volume 11, Number 4, page 15

Finite time exergoeconomic performance optimization of a universal irreversible heat-engine cycle model, which consists of two constant thermal-capacity heating branches, two constant thermal-capacity cooling branches and two adiabatic branches, is investigated by taking the profit rate criterion as the optimization objective. The analytical formulae for power, efficiency and profit rate function of the universal irreversible heat-engine cycle model with the losses of heat transfer, heat leakage and internal irreversibility are derived. The focus of this article is to search the compromised optimization between economics (profit rate) and the energy utilization factor (efficiency) for irreversible cycles. Moreover, analysis and optimization of the model are carried out in order to investigate the effects of these losses and cycle process on the performance of the universal irreversible heat-engine cycle model using numerical examples. The results obtained herein include the performance characteristics of seven typical irreversible heat engines, including Carnot, Diesel, Otto, Atkinson, Brayton, Dual and Miller cycles.     

High-Pressure Synthesis of Perovskites Pb(Li1/4Nb3/4)O3 and Pb(Li1/4Ta3/4)O3

Complex perovskite-type compounds with the general formula Pb(B⁺_1/4B⁵⁺_3/4)O₃, where B⁺= Li⁺ and B⁵⁺= Nb⁵⁺ or Ta⁵⁺, were synthesized using a high-pressure technique and studied by X-ray powder diffraction. The X-ray patterns were indexed on the basis of a cubic cell with a ₀= 4.071 Å for Pb(Li_1/4 Nb_3/4)O₃ and a ₀= 4.052 Å for Pb(Li_1/4Ta_3/4)O₃. Electrical properties of the new perovskites were also studied.     

Preparation of silicon oxide films by ultraviolet-assisted rf plasma-enhanced chemical vapour deposition

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Identification method in environmental systems and its application to water pollution

An identification algorithm is presented for a pollution source distributed along a river. The water quality is described by a couple of partial differential equations of the first order or a parabolic one. This problem, after transformation, results in the Fredholm integral equation of the first kind, which is non-well posed in the sense of Hadamard. The solution does not continuously depend on the observed data. The application of the regularization method proposed by Tikhonov (1963) yields a stable algorithm for the identification problem. Some simulation examples are given to illustrate the applicability of this method to environmental control systems based on the convective or dispersive phenomena.     

一种用于自律搬运车导航的混合式视觉方法

For the autonomous guided vehicle (AGV) used mainly in unfixed work fields, a machine vision method was proposed for the navigation system, in which a series of navigation-signs are placed along the travel route. The navigation system detects and recognizes these signs, and accordingly informs the travel control system. In order for the navigation to have balanced ability of 1) covering a large area and 2) recognizing details of the sign, the proposed vision method was designed to be a hybrid one, using both the stereo vision and the traditional 2D template matching. The former implemented a coarse recognition function for above 1), and the later implemented a fine recognition function for above 2). The results from the coarse recognition were used in the fine recognition for the gaze control to input suitable 2D image of the signs. Experiments on a prototype system show the feasibility of the proposed hybrid method in achieving the objective specifications for a typicalb AGV.     

Present Status of JT-60SA Project and Development of Heating Systems for JT-60SA

Present status of the JT-60SA (JT-60 Super Advanced) project, implemented jointly by Europe and Japan since 2007, is described. The design of the main tokamak components was completed in late 2008, and all the scientific missions are preserved to contribute to ITER and DEMO reactors. The construction of the JT-60SA has begun with procurement activities for the superconducting magnet systems, vacuum vessel, in-vessel components and other components under the relevant procurement arrangements between the implementing agencies of JAEA (Japan Atomic Energy Agency) in Japan and Fusion for Energy in Europe. Designs and developments of the auxiliary heating systems for JT-60SA have been progressing at JAEA so as to provide the total injection power of 41 MW for 100 s.