Formation of Metastable Rare-Earth Iron Garnet by Splat Quenching

The droplet with Nd _x Sm_{3− x} Fe₅O₁₂ composition was undercooled in an aerodynamic levitator and splat quenched by copper anvils in order to obtain a metastable garnet with a solubility limit larger than the phase equilibrium solubility limit, x =0.375, for the Nd _x Sm_{3− x} Fe₅O₁₂ system. The peaks of the garnet were identified with the peaks of the perovskite by powder X-ray diffraction (XRD), although the peak intensity for the garnet decreased with increasing the Nd substitution from x =0.43 to 0.2, and finally disappeared at x =2.2. When the garnet was annealed at 1570 K for 24 h in air, it transformed into a mixture of perovskite and hematite, which indicates that the garnet obtained was the metastable phase. Moreover, the amorphous phase was found in the central part of all the samples even at x =2.2, which was confirmed by micro-focus XRD. The formation of the constituent phases in the as-quenched sample was discussed using a continuous cooling transformation diagram.     

Characteristic Evaluation for Volatile Components of Soluble Coffee Depending on Freeze-Drying Conditions

Abstract

Volatile aroma compounds of freeze-dried soluble coffee were investigated to evaluate the effects of freeze-drying temperature conditions on their intensities and aroma characteristics by employing both GC/MS and charm-analysis, which is a GC/Olfactometry (GC/O) method. The coffee solutions with 40% solid content were freeze-dried changing freezing and drying temperatures. According to the results, it was demonstrated that the compounds identified based on human olfactory sense were different from those detected by GC/MS, and that the GC/O analysis method enabled evaluation of the characteristics and intensity of each compound as well as aroma profiles under various freezing and drying temperatures. Subsequently, GC/O method was found to be effective to detect and identify the volatile compounds giving the aroma peculiar to freeze-dried coffee, and useful to obtain the fundamental information for designing the optimal aroma characteristics of final product to conform the consumer preference based on the characteristic changes in aroma affected by freeze-drying conditions.     

Photocatalytic inactivation and removal of algae with TiO<Subscript>2</Subscript>-coated materials

The capabilities of TiO₂-coated materials for the inactivation and removal of algae were investigated. As supports for TiO₂, non-woven fabric and Ni foam were chosen. To evaluate the ability of noble metal cocatalyst additions to facilitate the photocatalytic algal inhibition of TiO₂-coated materials, Pd nanoparticles were deposited on non-woven fabric-supported TiO₂ by photoelectrochemical deposition. The fabric-supported Pd/TiO₂ showed higher inhibition activity for algal growth compared to the fabric-supported TiO₂ without Pd. In addition, Ni foam-supported TiO₂ also showed high inhibition activity, both in laboratory-scale tests and open-air tests. Therefore, TiO₂-coated materials with suitable coating methods such as the use of cocatalysts or large surface area can substantially inhibit algal growth. The ability of the TiO₂-coated materials to inhibit algae correlated well with their activity for the photocatalytic decolorization of methylene blue, suggesting a nonspecific mechanism in the breakdown of cellular structures.     

Measurement of the thermal conductivity of molten InSb under microgravity

Thermal conductivity of molten InSb was measured on board the TEXUS-24 sounding rocket by the transient hot-wire method using the originally designed thermal conductivity measurement facility (TCMF). Measurements made through this facility were affected by natural convection on the ground. This natural convection was confirmed to be sufficiently suppressed during a microgravity environment. The thermal conductivity of molten InSb was 15.8 and 18.2 W·m^–1·K^–1 at 830 and 890 K, respectively.     

Effect of substituting cerium-rich mischmetal with lanthanum on high temperature properties of die-cast Mg–Zn–Al–Ca–RE alloys

Mg–Zn–Al–Ca–RE alloys have been found to be promising materials for substituting aluminum alloys used for automatic transmission case applications in the automobile industry. Particularly, Mg–0.5%Zn–6%Al–1%Ca–3%RE (ZAXE05613) alloy exhibits comparable creep resistance as ADC12 die-casting aluminum alloy that is currently used for automatic transmission case applications. Changing the rare earth (RE) content of the alloy from mischmetal to lanthanum gives a further improvement in the creep properties of the alloy. Lanthanum addition results in the crystallization of a large amount of acicular Al₁₁RE₃ (Al₁₁La₃) compound along the grain boundaries as well as across the grain boundaries and this effectively controls grain boundary sliding and dislocation motion in the vicinity of the grain boundaries. As a result, die-cast ZAXLa05613 alloy exhibits a higher creep resistance than that of ZAXE05613 alloy.     

Experimental study on time evolution of Marangoni flow instability in molten silicon bridge

Temperature oscillations due to Marangoni flow instability in molten silicon half zone bridges with various aspect ratios of As = 0.5–2.0 were measured using six thermocouples set azimuthally 60^° apart in the liquid bridge close to the cold rod. The Marangoni number was estimated to range from 3000 to 14000, based on the measured axial temperature difference. Fourier spectra of the temperature oscillations were broad and continuous; each peak was not clearly distinguished but rather appeared as a frequency band. Thus, the convection was estimated to be turbulent-like. The time evolution of the azimuthal wave number was observed by analyzing the time-dependence of the phase relationship of the temperature oscillation detected by the six thermocouples. Analyzing the mode appearance coefficient MAC as a function of the aspect ratio, the relationship between the azimuthal mode number m and the aspect ratio As was observed to be m ? As ≈ 2.4; the basic structure of flow instability is sustained even under high Marangoni number. The temperature oscillation data was decomposed into that for each frequency band by using wavelet analysis. The frequencies for the m = 1 and m = 3 modes were estimated to be 0.08 to 0.2 Hz and 0.01 to 0.2 Hz, respectively.     

Specific Gut Microbial Environment in Lard Diet-Induced Prostate Cancer Development and Progression

Lard diet (LD) is a risk factor for prostate cancer (PCa) development and progression. Two immunocompetent mouse models fed with isocaloric specific fat diets (LD) enriched in saturated and monounsaturated fatty acid (SMFA), showed significanftly enhanced PCa progression with weight gain compared with a fish oil diet (FOD). High gut microbial divergency resulted from difference in diets, and the abundance of several bacterial species, such as in the orders Clostridiales and Lactobacillales, was markedly altered in the feces of LD- or FOD-fed mice. The proportion of the order Lactobacillales in the gut was negatively involved in SMFA-induced body weight gain and PCa progression. We found the modulation of lipid metabolism and cholesterol biosynthesis pathways with three and seven commonly up- and downregulated genes in PCa tissues, and some of them correlated with the abundance of the order Lactobacillales in mouse gut. The expression of sphingosine 1-phosphate receptor 2, which is associated with the order Lactobacillales and cancer progression in mouse models, was inversely associated with aggressive phenotype and weight gain in patients with PCa using the NCBI Gene Expression Omnibus database. Therefore, SMFA may promote PCa progression with the abundance of specific gut microbial species and overexpression of lipogenic genes in PCa. Therapeutics with alteration of gut microbiota and candidate genes involved in diet-induced PCa progression may be attractive in PCa.     

Effects of visual cue and spatial distance on exitability in electronic negotiation

We examined the effects of the visual anonymity of self and spatial distance on exitability in electronic negotiation in a role-play experiment. Exitability is the psychological factor that causes one to perceive the negotiation as unstable. We predicted that the lack of visual information and the spread of spatial distance would reduce anticipation of retaliation, make the continuation norm less salient, and prompt to exit from the current negotiation. Visual anonymity was manipulated by two conditions (visual anonymity or non-anonymity conditions). Spatial distance was manipulated by two conditions (remote or close conditions). Forty-three students were assigned in one of these four conditions, and negotiated. The results showed both the visual anonymity and remote distance inhibited the activation of continuation norm, prompted to exit from the current negotiation.     

Facile fabrication and photocatalytic application of Ag nanoparticles-TiO2 nanofiber composites

A novel chemical method has been developed for the fabrication of Ag nanoparticles-coated TiO2 nanofiber composites. The method involves dispersion of TiO2 nanofibers in silver salt solution under ultrasonication, followed by addition of sodium citrate as a reducing agent. The Ag-coated TiO2 composites were characterized by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron microscopy (XPS). Furthermore, the photocatalytic performance was evaluated by the photocatalytic degradation of methyl orange under UV-light irradiation. It was found that the heterogeneous Ag-TiO2 composite showed a higher activity than the pure TiO2 nanofiber; the enhanced activity can be attributed to the excellent distribution and interaction of Ag nanoparticles with the TiO2 nanofiber support. A plausible mechanism for the formation of the Ag-coated TiO2 composite and reasons for the enhancement of photocatalytic activity are also discussed.     

Non-contact measurement of surface oscillation due to Marangoni flow instability in a silicon liquid bridge by phase-shift interferometry

In order to investigate Marangoni flow instability of molten silicon, surface oscillation of a silicon liquid bridge with various aspect ratios at high Marangoni numbers, such as Ma ≥ 2400, was observed by using real-time phase-shift interferometry. By analyzing phase distribution of the phase-shift interferograms using FFT (fast Fourier transformation) and wavelet transformation, we found that two frequency bands exist in surface oscillation. Their central frequencies are 0.1–0.5 Hz for a lower band and 0.7–1.3 Hz for a higher band, respectively. Central frequency decreases with increase in aspect ratio. The lower frequency bands, which include m = 1 and m = 3 modes, appear continuously, whereas the higher frequency bands appear intermittently.