Dynamic fatigue behavior of cracked piezoelectric ceramics in three-point bending under AC electric fields

This paper describes an experimental and analytical study on the dynamic fatigue behavior of cracked piezoelectric ceramics under AC electric fields. Constant load-rate testing was conducted in three-point bending with the single-edge precracked-beam specimens. The crack was created normal to the poling direction. The effects of AC electric fields and loading-rate on the fracture load were examined. A phenomenological model of domain wall motion was also used in finite element computation, and the energy release rate for the permeable crack model was calculated. The effect of AC electric fields on the critical energy release rate was then examined. The results suggest that (1) the fracture load of PZT ceramics decreases as the load-rate decreases; (2) an overall decrease in the fracture load occurs when testing under AC electric fields; and (3) the critical energy release rate is not very affected by the AC electric fields.     

Deformation and Crushing of Particles of Cement Treat Granulate Soil

Cement Treat Granulate Soil (CTGS), a new artificial granular material, has been developed recently by mixing the dredged marine clay with appropriate amounts of cement and polymer. The CTGS particles are crushable and deformable, thus forming a compressible material. Besides being a lightweight material, CTGS is a granular material, and is therefore expected to be applied in reclamations or as a back fill or subsoil materials. This study investigates the deformation and crushing of the CTGS particles and their effects on the stress-strain behaviors. The comprehensive investigation of the principle of treatment, the micro-structure of particles, triaxial stress-strain behaviors, induced particle crushing and particle deformation are first presented via the experimental work done on two types CTGS produced from a lean-mixture design of cement and polymer. Subsequently, the results of X-ray Computer Topography (CT) scanners along with triaxial CD tests on CTGS and conventional gravel having rigid particles are presented. The test results reveal local failure mechanisms between the individual particles of the CTGS and gravel, from which the failure models of the granular materials formed by deformable and crushable grains and non-crushable grains are interpreted.     

Determination of Unconjugated Carbon Sites in Benzenoid Derivatives

Rules 1–4 for judging whether or not a given hydrocarbon benzenoid derivative is topologically stable, are proved. Here each conjugated derivative is expressed as a hexagon-shaped molecular (hydrogen-suppressed) graph, and has unconjugated carbon sites such as methylene, carbonyl, and radical groups, in its boundary.     

Phase Transformation Behavior of a Pyrochlore‐Type CeO2–ZrO2 Binary Compound

The phase transformation behavior of the superlattice structure of a CeO₂–ZrO₂ pyrochlore‐type binary compound (CP) was investigated so as to better understand how to improve the thermal stability of such a system. CP was synthesized through high‐temperature reduction of a conventional CeO₂–ZrO₂ solid solution with a 1:1 molar ratio of Ce and Zr. High‐resolution transmission electron microscopy and selected‐area electron diffraction clearly revealed that the pyrochlore structure of CP transformed to the standard disordered cubic fluorite or tetragonal zirconia structure after having been subjected to a high‐temperature durability test; moreover, it was determined that this phase transformation moves inward from the crystallite surface. This discovery suggests a new method by which to improve upon this material for practical applications.     

Coupling simulation system of annual building energy and microclimate

We have developed a simulation system for a year-round assessment of environmental comfort, energy conservation, and CO₂ emissions in buildings and street blocks where active utilization of sunshine, vegetation and solar energy resources is fully considered. An analysis model has been constructed for handling interactions between highly complex street-block wide solar radiation patterns and building air-conditioning load. As a demonstration case of the present system, coupled solar radiation-thermal load analysis for an eleven-story office building has been performed. By comparing the result of a building located in a city block with a reference case of a self-standing building, the proper arrangement of buildings and spaces such as solar reflectance of building surface may be proposed.     

Study of the acceptability of a parking deposit system as an alternative road pricing scheme

While road pricing (RP) is considered one of the most effective means of traffic demand management (TDM), its poor acceptability has been the greatest impediment to its implementation. The authors propose a `parking deposit system? (PDS) as an alternative RP scheme, and the aim of this study is to examine PDS?s superiority focusing primarily on acceptability. To mutually verify the acceptability of PDS and conventional RP, the authors conducted a survey in the city of Nagoya, the third-largest incorporated city and the fourth most populous urban area in Japan. This survey distributed a comprehensive questionnaire to visitors and business establishments, in and around the city, eliciting a significant response. In this study process, the authors firstly built the decision-making structure model of RP/PDS by public/business establishment to clarify the decisionmaking mechanism in detail. Secondly, the approval models were built to estimate the differentia of the acceptability between RP and PDS. From this study PDS can be thought to have the higher acceptability, and to be useful measure as an alternative RP scheme.