Ferroelastic domain structure and phase transition in single-crystalline [PbZn1/3Nb2/3O3]1-x[PbTiO3]x observed via in situ x-ray microbeam

(1-x)Pb(Zn_1/3Nb_2/3)O₃-xPbTiO₃ ((1-x)PZN-xPT in short) is one of the most important piezoelectric materials. In this work, we extensively investigated (1-x)PZN-xPT (x = 0.07–0.11) ferroelectric single crystals using in-situ synchrotron μXRD, complemented by TEM and PFM, to correlate microstructures with phase transitions. The results reveal that (i) at 25 °C, the equilibrium state of (1-x)PZN-xPT is a metastable orthorhombic phase for x = 0.07 and 0.08, while it shows coexistence of orthorhombic and tetragonal phases for x = 0.09 and x = 0.11, with all ferroelectric phases accompanied by ferroelastic domains; (ii) upon heating, the phase transformation in x = 0.07 is Orthorhombic → Monoclinic → Tetragonal → Cubic. The coexistence of ferroelectric tetragonal and paraelectric cubic phases was in-situ observed in x = 0.08 above Curie temperature (T_C), and (iii) phase transition can be explained by the evolution of the ferroelectric and ferroelastic domains. These results disclose that (1-x)PZN-xPT are in an unstable regime, which is possible factor for its anomalous dielectric response and high piezoelectric coefficient.     

Effects of Using Alternative Extreme Pressure (EP) and Anti-Wear (AW) Additives with Oxy-Nitrided Samples

Oxy-nitriding is a widely used industrial process aiming to improve the tribological properties and performance of components. Previous studies have shown the effectiveness of the treatment with friction and wear performance, but very few have focussed on optimising this behaviour. The lubrication properties of several EP and AW additives were examined to investigate their effectiveness in improving the tribological properties of the layers formed after treatment. Previous studies showed the presence of an oxide layer on the sample could improve the effectiveness of the sulphurised olefin (SO) and tricresyl phosphate (TCP) additives. The friction and wear behaviour of oxy-nitrided samples were analysed using a tribometer and surface profiler. Scanning electron microscope, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were employed to identify the morphologies and chemical compositions of the treated surface before and after testing. No real effect on friction was observed when using the SO or TCP additives, mostly due to lack of interaction with the less reactive iron nitride layer and their roles as anti-wear additives. However, when the zinc dialkyldithiophosphate-containing lubricant was used, a higher friction coefficient was observed. Greater improvements in anti-wear properties with the presence of additives in comparison with only using base oil were reported, with the TCP additive producing the lowest wear rates. The study effectively demonstrated that the additive package type used could impact the tribological and tribochemical properties of oxy-nitrided surfaces.     

Long-term field survey on thermal adaptation in office buildings in Japan

A long-term field survey was conducted with six buildings in order to investigate how the occupants adapt to the indoor climate in office buildings in Japan. More than 5000 questionnaires and corresponding indoor temperatures were collected. Clothing adjustment was observed to be related to outdoor temperature and indoor temperature, as well as dress codes. No considerable differences were found on the thermal perceptions between two groups of buildings, which provided different levels of opportunity for controlling indoor climate. With both groups, the preferred SET* was always close to 26 °C. The comfort temperature was estimated from the results of clothing adjustment and the preferred SET*. The gradient of the comfort temperature to outdoor temperature was found to be between the adaptive model for centralized HVAC and for natural ventilation. It could be caused by that the major part of the occupants in the present study had more opportunity to control their thermal conditions than in the centralized HVAC buildings (i.e. operable windows, controllable HVAC or personal fans).     

Fire Safety Performance of Japanese Traditional Wood/Soil Walls and Implications for the Restoration of Historic Buildings in Urban Districts

Grass-root research activities to clarify fire safety performance of Japanese traditional wooden construction are introduced. The activities aim to resolve conflict between the restoration of historic buildings and the reduction of risk and hazard of urban fires. Among various activities, scope and results of fire resistance tests on traditional soil wall assemblies supported by timber frame are reported in detail. The test results indicate an encouraging prospect for the rational fire safety assessment of historic buildings and further development of fire-safe traditional constructions for the restoration of historic buildings and historic urban districts.     

Profiles of mean wind speeds and vertical turbulence intensities measured at seashore and two inland sites using Doppler sodars

The authors’ group has been conducting full-scale measurements of wind velocities with Doppler sodars. It is very important to accurately assess the profiles of mean wind speeds and turbulence intensities in relation to terrain roughness. In this study, the profiles were evaluated for all data measured over a long period at a seashore and two inland sites. It is confirmed that for strong winds the profiles can be approximated by a single power law at altitudes between 50 and 340 m. The power law exponents of the mean wind speed profiles are approximately 0.1 for wind from the sea and 0.2-0.3 for wind blown over land. Those of the turbulence intensity profiles are approximately 0 and −0.2 to 0.4, respectively.     

Total emission control for managing regional water quality: a game theoretic decision process

A simple game theoretic model with hierarchical structure is developed for regulating the total amount of pollutant discharged by all the effluent producers in a given region, where the allowable limit on total emission, that is the environmental carrying capacity, is assumed to be given. It is proposed that the total emission is to be allocated amongst all the polluters so as to maximize the social benefit, and that the social benefit is to be allocated through taxation on the companies under the criterion of impartiality. The concept of impartiality is defined as equal individual satisfaction for the polluters who cooperate. This concept is applied to solve the characteristic function game. A numerical example is included.     

Structural,mechanical, and electrical properties of carbon nanoparticles synthesized from diesel

We studied the elemental analysis, structural morphology, mechanical, and electrical properties of carbon nanoparticles synthesized from diesel. The spherical carbon particle size in the range of about 10 to 80 nm in diameter was observed in scanning electron microscope (SEM) studies that were identified by Atomic force microscopy (AFM) study as an aggregation of carbon particles of average size 2.5 nm. The surface rms of carbon nanoparticle thin film (CNTF) was measured directly by AFM and found 0.22 nm. The Derjaguin–Muller–Toporov (DMT) elastic modulus of carbon nanoparticles (CNPs) was measured by PeakForce QNM mode of AFM. The minimum and maximum elastic modulus was measured of 0.40 GPa and 43.89 GPa, respectively. The resistivity, conductivity, magneto resistance, mobility, and average Hall co-efficient were measured by “Ecopia Hall-effect measurement system” by four-point Van der Pauw approach at ambient condition. We demonstrated I–V characteristic at the Indium/CNTF thin film interface, which is accompanied by rectifying behavior.     

Effect of the dilation caused by helium bubbles on edge dislocation motion in α-iron: molecular dynamics simulation

Various types of nanometric defects such as voids and helium (He) bubbles produced by high-energy neutron irradiations are known to degrade the mechanical properties of irradiated materials. In this study, we have evaluated the obstacle strength of He bubbles to the mobility of an edge dislocation in α-iron for 2 and 4 nm bubbles with He-to-vacancy (He/V) ratios ranging from 0 to 1 at 300 and 500 K, by molecular dynamics simulation. Results showed that as the He/V ratio increases, the obstacle strength needed for the release of a dislocation from the bubble becomes stronger up to a moderate He/V ratio (0.6 and 0.4 for 2 and 4 nm bubbles, respectively, at both temperatures), and a further increase in the He/V ratio leads to weakening of the obstacle strength. For He/V = 1, the obstacle strengths are 10–30% weaker than those at moderate He/V ratios depending on the bubble size and temperature. The extent of obstacle strength was found to be correlated with the dilation caused by He bubbles depending on the bubble size, He/V ratio, and temperature.     

Voltage Control of Static Var Compensator for a Remote System Interconnected by Long‐Distance AC Cables

The voltage variation in a remote system is large when the system is connected by long‐distance AC cables due to the cable capacitance. In Japan, the longest 54‐km 66‐kV AC submarine cable interconnection between the Kyushu mainland and Goto Islands was commissioned in 2005. It was requested to mitigate the voltage variation caused by switching off and on one circuit of the two circuits in the AC cables when a fault occurs. Since the conventional voltage control methods such as transformer tap changer or shunt capacitor and reactor banks are not sufficient because of their slow response time, a static var compensator (SVC) was installed on the Goto Islands. In such an application, an SVC control method should be developed so as not to override the existing voltage control systems. This paper describes the SVC control method developed for the Goto Islands AC interconnection project, which can be applied to similar situations. The effectiveness of the control method was verified by the results of effective value simulation and of field testing, which was implemented before the SVC was commissioned in 2007. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(3): 19–30, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22337