Phase diagram calculations of ZrO2-based ceramics with an emphasis on the reduction/oxidation equilibria of cerium ions in the ZrO2-YO1.5-CeO2-CeO1.5 system

Phase diagram calculations that were made previously for the ZrO₂-MO _m/2 (m = 2, 3, 4) systems and for the ZrO₂-YO_1.5-MO _m/2 (M = transition metals) systems have been extended to the ZrO₂-YO_1.5-CeO₂(-CeO_1.5) system to make an attempt to explain (1) thermogravimetric (TG) results as a function of oxygen potential, (2) electronic conductivity as a function of oxygen potential, and (3) a miscibility gap observed in air. The interaction parameters for the CeO₂-CeO_1.5-YO_1.5 system were obtained from the reported oxygen nonstoichiometry in CeO_2−x and rate earth doped ceria, (Ce,RE)O_2−δ . The interaction parameters for the ZrO₂-CeO₂ subsystem were obtained so as to reproduce the observed miscibility gap at 1273 K. Those thermodynamic properties can reproduce consistently the experimental behaviors of the electronic conductivity and the TG results in the (Zr_1−x Ce _x )_0.8Y_0.2O_1.9 solid solutions; these indicate the enhancement of reduction of CeO₂.     

Fitting a woven cloth model to a curved surface: dart insertion

If a woven cloth composite “ply” cannot fit a surface exactly, “darts” must be cut. Algorithms that define these darts for a CAD system resolve anomalies in the 3D ply     

A quadruple-scanning-probe force microscope for electrical property measurements of microscopic materials

Four-terminal electrical measurement is realized on a microscopic structure in air, without a lithographic process, using a home-built quadruple-scanning-probe force microscope (QSPFM). The QSPFM has four probes whose positions are individually controlled by obtaining images of a sample in the manner of atomic force microscopy (AFM), and uses the probes as contacting electrodes for electrical measurements. A specially arranged tuning fork probe (TFP) is used as a self-detection force sensor to operate each probe in a frequency modulation AFM mode, resulting in simultaneous imaging of the same microscopic feature on an insulator using the four TFPs. Four-terminal electrical measurement is then demonstrated in air by placing each probe electrode in contact with a graphene flake exfoliated on a silicon dioxide film, and the sheet resistance of the flake is measured by the van der Pauw method. The present work shows that the QSPFM has the potential to measure the intrinsic electrical properties of a wide range of microscopic materials in situ without electrode fabrication.     

Water Network in Room-Temperature Ionic Liquid: <Emphasis Type="Italic">N,N</Emphasis>-Diethyl-<Emphasis Type="Italic">N</Emphasis>-Methyl-<Emphasis Type="Italic">N</Emphasis>-2-Methoxyethyl Ammonium Tetrafluoroborate

Crystal structures of room-temperature ionic liquid (RTIL)-H₂O mixtures are determined by the X-ray diffraction method. The RTIL is N,N-diethyl-N-methyl-N-2-methoxyethyl ammonium tetrafluoroborate, [DEME][BF₄]. At 0.9 mol pct H₂O, two kinds of superstructures occur simultaneously without a strain. Also, the volume of the unit cell is very small only at 0.9 mol pct additives. This relates to the composite domain structure, including a twin-related one, as an elastic anomaly. At other water concentrations, such an extraordinary behavior is not observable. By assuming a sublattice having an equivalent lattice constant, a water network at 1 mol pct H₂O is simulated using a Monte Carlo (MC) method. The network develops over the medium range in the simulation box.     

Microstructure of the interface in magnesium alloy to aluminium alloy dissimilar joints produced by friction stir welding

Friction stir welding (FSW) is a process that was developed by the UK Welding Institute (TWI) in 1991.¹ Because of its status as a solid-phase joining process operating at a temperature below the melting point of the materials being joined, FSW usually generates less residual stress than fusion welding, being also advantageously free from fume, porosity, and solidification cracking. The mechanical properties of welds are equivalent or superior to those of conventional welds and offer a high level of reliability. Other merits of FSW include relatively low equipment costs, low operating costs, and no required training. For this reason, in the decade or so since the principle of FSW was invented, the process has seen a number of practical applications in railway and ship structures as well as for rocket fuel tanks in the aerospace field² and continues to draw considerable attention by the engineering industry worldwide. The foregoing applications, however, all refer to components produced from aluminium alloys.     

Human herpesvirus 6 infection as a risk factor for the development of severe drug-induced hypersensitivity syndrome

OBJECTIVES: To test suitability of radiographic evaluation of lung lesions as a substitute for lung lesion scores derived by examination at necropsy in challenge-exposure models of bovine pneumonia. ANIMALS: 10 calves selected by body weight from 20 multiple-source male Holstein calves approximately 1 to 2 months old enrolled in a Pasteurella multocida challenge-exposure study. PROCEDURE: Calves were paired on the basis of weight and randomly assigned within pairs to vaccine or control (saline solution) group. By use of deep tracheal cannulation, calves were challenge exposed with a culture of virulent P multocida, observed for 10 days, euthanatized, and necropsied, and the lungs were scored for pneumonic lesions. Radiographic views of the lung fields of the calves were taken before challenge exposure and before necropsy and were evaluated for alveolar disease by a veterinary radiologist. Lung lesion scores were compared with radiographic evaluations. RESULTS: There was a strong and significant correlation (R2 = 0.91, P < 0.001) between results of the evaluation of postchallenge-exposure radiographs and necropsy results. There also was also strong and significant correlation (R2 = 0.90, P < 0.001) between evaluation of the prechallenge-exposure radiographs and necropsy results. CONCLUSIONS: Radiographic evaluation of lung lesions correlates well with lung lesions found at necropsy. The findings emphasize the need for caution in interpreting the results of challenge-exposure studies of bovine respiratory tract disease in which small numbers of calves are studied.     

Liquid-Phase-Assisted Sintering of Calcium-Doped Lanthanum Chromites

Investigations have been made on the low-temperature sinterability of calcium-doped lanthanum chromites which are to be used as interconnectors in solid oxide fuel cells (SOFCs). Nominally chromium deficient lanthanum calcium chromites (La_0.7Ca_0.3Cr₁-_yO₃, y = 0.02) were found to be sinterable to 94% theoretical density at 1573 K in air, whereas no densification was observed for samples with y = 0. The two-step shrinkage process suggests a liquid phase sintering mechanism with calcium oxychromates playing an important role as the liquid phase. After sintering at 1573 K, calcium-rich substances remained at grain boundaries.