Carbon Dioxide Sensor Mechanism of Porous Hydroxyapatite Ceramics

Hydroxyapatite and Cl⁻ -containing hydroxyapatite powders are prepared and characterized. Reversible substitution of CO^2-₃ for OH⁻ at the surface is presumed to be responsible for the sensor function. The role of Cl⁻, which is necessary to realize the sensor function and is incorporated during soaking treatment, is considered as follows. It may reduce the strain caused by the incorporation of CO^2-₃ (which is larger than OH⁻), and, hence, promote the reversible substitution reaction. This behavior is presumed because Cl⁻ -containing hydroxyapatite samples exhibit sensor characteristics typical of CO₂ without any treatment.     

Influence of low temperature working on microstructure and mechanical properties of AI-7Si-(Fe) alloys

Changes in the microstructure and mechanical properties of Al-7Si-(Fe) alloys by low temperature working have been investigated. The size and shape of eutectic Si and intermetallic AlSiFe compound were controlled by the low temperature working process. This process consisted of repeated cold working at 77 K and recovery treatment at 793 K. By applying this process to the Al-7Si-1Fe alloy, the eutectic Si and acicular Fe compound(β-AlSiFe) phases were broken down to the size of 2-3 μm, with spherical shape. The refined particles were uniformly distributed, and a fine microstructure was obtained. The strength and elongation of Al-7Si-1Fe alloy increased as the temperature was lowered due to the microstructural refinement. This elongation was well reflected in the fracture surface.     

Synergistic Extraction of Am(III) and Eu(III) by Tris(2‐pyridylmethyl)Amine with Various Anions in 1,2‐Dichloroethane

The extraction equilibria of Am(III) and Eu(III) by using a tripodal ligand, tris(2‐pyridylmethyl)amine (tpa), with various lipophilic anions have been investigated. The extractability of both Am(III) and Eu(III) was increased by the combination of tpa and counteranions due to a synergistic effect. The separation factors between Am(III) and Eu(III) were also increased from 7.6 to 49 by the combination of counteranions and organic solvents. The extraction equilibria of Am(III) and Eu(III) with tpa in 1,2‐dichloroethane were determined by slope analysis. It was found that three anions and one molecule of the ligand coordinated to Am(III) and Eu(III) was extracted regardless of the anions.     

Geometry Dependence of Magnetization Reversal in Nanocomposite Alloys

The geometrical optimization of aligned hard-soft permanent-magnet nanocomposites is investigated by model calculations. Considered criteria are the shapes of the soft and c-axis-aligned hard phases, the packing fraction of the soft phase, and magnetostatic interactions. Taking into account that the energy product is enhanced via the volume fraction of the soft phase, subject to maintaining coercivity, we find that the best structures are soft-magnetic cubes as well as long rods with a square cross section. Comparing embedded soft cubes with embedded soft spheres of the same size, our nucleation-field analysis shows that the volume fraction of the soft phase is enhanced by 91%, with a coercivity reduction of only 25%. Magnetostatic interactions often but not always deteriorate the permanent-magnet performance, as exemplified by the example of MnBi:FeCo bilayers and multilayers.     

Spectroscopic studies of triboluminescence from a sliding contact between diamond, SiO2, MgO, NaCl, and Al2O3 (0001)

We have measured spectra of the light emission from the frictional contact between the pin of natural diamond, synthetic fused silica, MgO, or NaCl and the disk of quartz or synthetic sapphire in a vacuum in the wavelength range between 380 and 1000 nm. Each spectrum shows the relaxation of electronic excited vacancies, which are thought to be produced at the solid surface by mechanical abrasion.     

Automatic small blend recognition from B-rep models for analysis

The recognition and suppression of small features from B-rep models play an important role in effectively generating the qualified mesh for analysis. This paper presents a new algorithm for recognizing small blends automatically for the purpose of mesh generation. The algorithm first transforms the input B-rep model into an aggregation of faces. Then, each face is judged to be a blend or not based on matching conditions. At last, the blends with larger physical sizes than a threshold value are excluded. The innovations lie in the recognition conditions and the unique calculating procedure of the blend physical size. Several examples are given to demonstrate the validity and applicability of the algorithm.     

Measurement of the flood discharge of a small-sized river using an existing digital video recording system

In this study, a closed-circuit television (CCTV) system, installed for surveillance purposes, is utilized to measure the flow rate during a flood. The procedure to determine both the angle and scale-factor of the camera is described. Then, image analysis techniques, namely the direct visual measurement method, Large-Scale PIV (LSPIV) and Space-Time Image Velocimetry (STIV), are applied to the video images recorded by the CCTV camera. The results of these methods and the conventional float measurement are compared. In addition, the accuracy of the respective methods is discussed. A set of low-quality video images of a flood during a thunderstorm that occurred under the dark ambient conditions (midnight) is analyzed using three image-based methods. The transition of the flow rate during the event is successfully estimated.     

Azimuthal wave number control of oscillatory thermocapillary convection in a liquid bridge

Thermocapillary convection in a half‐zone liquid bridge of high Prandtl number fluid is widely known to exhibit a three‐dimensional oscillatory flow after the onset of oscillation. The oscillatory flow presents ‘standing’ and ‘traveling’ flows depending upon the temperature difference between the top and bottom rods. In the oscillatory state, the flow shows a modal structure with an azimuthal wave number that depends on the aspect ratio of the liquid bridge and the intensity of the thermocapillarity expressed by the Marangoni number. The present study attempted to control the azimuthal wave number by heating the free surface locally with a prescribed frequency and intensity. The flow in the liquid bridge exhibited different modal structures depending on the heating conditions and a relationship between the frequency and the modal structure was obtained. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(7): 460–469, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20086     

Quantitative evaluation of perceived whiteness based on a color vision model

This article describes a new perceived whiteness index, C/V index, which focuses on the brightness‐enhancement effect of color components included in the spectral reflectance factor distribution of approximate white objects or in the spectral power distribution of illuminations. The index is developed on the basis of a color vision model. The perceived whiteness of 18 approximate white samples was evaluated, and then a predictability of the index was compared with 17 types of existing whiteness indices. As a result, the C/V index was one of the indices indicating the best predicting performance. The aforementioned findings show that the C/V index is effective in evaluating the perceived whiteness of approximate white objects and the brightness‐enhancement effect of color components is an important factor in determining the perceived whiteness. © 2009 Wiley Periodicals, Inc. Col Res Appl, 2010