Experiment study on fracture fixation with low rigidity titanium alloy

In order to investigate bone tissue reaction to the low rigidity titanium alloy of TNTZ in bone plate fixation, animal experiment with rabbit was performed with X-ray follow-up and histological observation. Experimental fractures were made in rabbit tibiae, and fixed by different bone plates of SUS316L, Ti–6Al–4V and TNTZ. Although there was no significant difference in fracture healing, bone atrophy was observed in cortical bone especially under the bone plate, which was different in time course among three materials. The bone atrophy under the bone plate was confirmed as porous or poor bone tissue in histological observation. In addition, the diameter of the tibia bone was increased in TNTZ as the result of bone remodeling with a new cortical bone. It is confirmed that the elastic modulus of the bone plate will naturally influence bone tissue reaction to the bone plate fixation according to the Wolff’s law of functional restoration.     

Thermal mixing characteristics of helium gas in high-temperature gas-cooled reactor, (I) thermal mixing behavior of helium gas in HTTR

The future high-temperature gas-cooled reactor (HTGR) is now designed in Japan Atomic Energy Agency. The reactor has many merging points of helium gas with different temperatures. It is needed to clear the thermal mixing characteristics of helium gas at the pipe in the HTGR from the viewpoint of structure integrity and temperature control. Previously, the reactor inlet coolant temperature was controlled lower than specific one in the high-temperature engineering test reactor (HTTR) due to lack of mixing of helium gas in the primary cooling system. Now, the control system is improved to use the calculated bulk temperature of reactor inlet helium gas. In this paper, thermal–hydraulic analysis on the primary cooling system of the HTTR was conducted to clarify the thermal mixing behavior of helium gas. As a result, it was confirmed that the thermal mixing behavior is mainly affected by the aspect ratio of annular flow path, and it is needed to consider the mixing characteristics of helium gas at the piping design of the HTGR.     

Vacuum ultraviolet photoionization mass spectra and cross-sections for volatile organic compounds at 10.5 eV

Vacuum ultraviolet single-photon ionization time-of-flight mass spectrometry (VUV-SPI-TOFMS) has been applied to the detection of volatile organic compounds (VOCs), including aromatic, chlorinated, and oxygenated compounds. Photoionization mass spectra of 23 VOCs were measured using SPI-TOFMS at 10.5 eV (118 nm). The limits of detection of VOCs using SPI-TOFMS at 10.5 eV were estimated to be a few ppbv. The mass spectra of 20 VOCs exhibit only the parent ion and its isotopes' signals. The ionization processes of the VOCs were discussed on the basis of the reaction enthalpies predicted by the quantum chemical calculations. Absolute photoionization cross-sections for 23 VOCs, including 12 newly measured VOCs, at 10.5 eV were determined in comparison to the reported absolute photoionization cross-section of NO.     

Synthesis of High-Purity Zirconium Fluoride for Fluoride Glass Fibers by Chemical Vapor Deposition

A technique for synthesizing ultra-high-purity ZrF₄ using chemical vapor deposition in a ZrBr₄–HF system is developed and a purification mechanism is clarified. The Fe concentration in ZrF₄ is evaluated at less than 10 ppb based on analysis of the transmission loss spectrum of a fiber prepared using synthesized ZrF₄. Purification is achieved mainly in a sublimation process of ZrBr₄, and purification efficiency is determined by sublimation temperature and activity of impurities in ZrBr₄. The concentration of transition-metal impurities in ZrF₄, synthesized by chemical vapor deposition in the ZrBr₄–HF system, is expected to be less than 1 ppb.     

Transparent Hydroxyapatite Prepared by Hot Isostatic Pressing of Filter Cake

Hydroxyapatite powder was synthesized and formed into a compact in an aqueous medium using a filter-cake method. The compact was hot isostatically pressed at 700° to 1000°C and 100 MPa for 2 h. Fully dense, transparent materials were obtained above 800°C. Both forming and densification methods were found to be important in obtaining transparent materials.     

Proposal of cause–effect pattern library for realizing sustainable businesses

Sustainable business design has gained growing interest in recent years. However, it is often difficult to clarify which business activities actually contribute to (or violate) the sustainability of the earth due to high complexity of environmental and economical system of our society. In order to help a business to generate sustainable business ideas handling this complexity in a systematic and comprehensive manner, this paper proposes a method to formulate a wide variety of causalities in our society into a cause–effect pattern library and illustrates how to use it for design and planning of sustainable businesses.     

Interaction control between endohedral metallofullerene and metal substrate by introducing alkanethiol self-assembled monolayer

The interaction control between endohedral metallofullerenes and a metal substrate has been demonstrated by introducing hexanethiol, octanethiol, and decanethiol self-assembled monolayers (SAMs) as the interlayer. We observe the electric properties of terbium endohedral metallofullerenes (Tb@C82) on alkanethiol SAMs with different chain lengths by scanning tunneling microscopy (STM) and spectroscopy (STS). Based on the comparison of the high-resolution STM images of a Tb@C82 molecule on hexanethiol and octanethiol SAMs, the interaction between Tb@C82 and a hexanethiol SAM is found to be larger than that between Tb@C82 and an octanethiol SAM; this is because at 68 K, the rotational states of Tb@C82 terminate only on the hexanethiol SAM. Furthermore, we find that the tunneling current-voltage characteristics of Tb@C82 on the hexanethiol SAM show the rectifying effects that are also caused by the molecular energy level shifts of Tb@C82 molecules due to the large interaction.     

Corrosion Behavior of Sialon Ceramics in Supercritical Water

The corrosion behavior of sialon ceramics was investigated in supercritical water at 450°C under 45 MPa for 2–50 h. α-sialon exhibited better corrosion resistance than β-sialon and α/β-sialon. Pitting corrosion with the formation of corrosion products was observed in the case of β-sialon and α/β-sialon. By contrast, the corrosion behavior of α-sialon was characterized by uniform corrosion with the formation of corrosion products. The degree of strength deterioration was strongly dependent on the corrosion morphology. The bending strength of α-sialon after corrosion for 30 h was about 90% of its initial strength, while the strength of β-sialon decreased to 65% of its original strength.     

Direct Observation of Internal Structure in Spray-Dried Alumina Granules

The internal structure of spray-dried alumina granules was characterized by optical microscopy by immersing them in a liquid having a refractive index close to that of alumina. This method provides a unique technique for the detailed analysis of the internal structure of spray-dried granules.