Thermal properties of redeposition layers in the JT-60U divertor region

Thermal properties of the redeposition layer on the inner plate of the W-shaped divertor of JT-60U have been measured with laser flash method so as to estimate transient heat loads onto the divertor. Morphology analysis of the redeposition layer was conducted with a scanning electron microscope. Measurement of a redeposition layer sample of more than 200 μm thick, which had been produced near the most frequent striking point, showed following results: (1) the bulk density of the redeposition layer is about half of that of carbon fiber composite material; (2) the specific heat of the layer is roughly equal to that of the isotropic graphite; (3) the thermal conductivity of the redeposition layer is two orders of magnitude smaller than that of the carbon fiber composite. This low thermal conductivity of the redeposition layer is considered to be caused by a low graphitization degree of the redeposition layer. The difference between the divertor heat loads and the loss of the plasma stored energy becomes smaller taking account of thermal properties of the redeposition layer on the inner divertor, whereas estimated heat loads due to the ELMs is still larger than the loss. This is probably caused by the poloidal distribution of the thermal properties.     

Preparation and properties of LiCoyMnxNi1−x−yO2 as a cathode for lithium ion batteries

The preparation of LiCo_yMn_xNi_1−x−yO₂ from LiOH·H₂O, Ni(OH)₂ and γ-MnOOH in air was studied in detail. Single-phase LiCo_yMn_xNi_1−x−yO₂ (0y0.3 and x=0.2) is obtained by heating at 830–900°C. The optimum heating temperatures are 850°C for y=0–0.1 and 900°C for y=0.2–0.3. Excess lithium (1z1.11 for y=0.2) and the Co doping level (0.05y0.2) do not significantly affect the discharge capacity of Li_zCo_yMn_0.2Ni_0.8−yO₂. The doping of Co into LiMn_0.2Ni_0.8O₂ accelerates the oxidation of the transition metal ion, and suppresses partial cation mixing. Since the valence of the manganese ion in LiMn_0.2Ni_0.8O₂ is determined to be 4, the formation of a solid solution between LiCo_yNi_1−yO₂ and Li₂MnO₃ is confirmed.     

Phase relations in the Fe-Pu-U ternary system

An isothermal section of the Fe-Pu-U ternary system at 650 °C was assessed in a previous study. In the present study, the predictions of the phase relations in the Fe-Pu-U system to higher and lower temperatures were performed by applying the interaction parameters determined at 650 °C. Differential thermal analysis (DTA) for the Fe-Pu-U alloys was also carried out to confirm the phase relations in the temperature region of 500 to 800 °C. Both results agreed well. On the basis of the predicted ternary phase diagram, the phase relations for a region surrounded by Fe₂Pu, Fe₂U, U, and Pu were described by a reaction scheme and a projection of the liquidus surface.     

Synthesis and Thermal Characterization of Novel Fluorene-Based Polysiloxane Derivatives

Three novel poly(tetramethylsilfluorenylenesiloxane) derivatives having different substituent at 9-position of fluorenylene moiety, i.e. dimethyl (P1), spirocyclohexyl (P2), and spirofluorenyl (P3) substituents, were obtained by polycondensation of novel three disilanol monomers, i.e. 2,7-bis(dimethylhydroxysilyl)-9,9-dimethyl- fluorene (M1), 2’,7’-bis(dimethylhydroxysilyl)-spiro(cyclohexane-1,9’-fluorene) (M2), 2,7-bis(dimethylhydroxysilyl)-9,9’-spirobifluorene (M3), respectively. P1–P3 exhibited the good solubility in common organic solvents, such as tetrahydrofuran (THF), chloroform, dichloromethane, and toluene. It was suggested from the differential scanning calorimetry (DSC) and the X-ray diffraction analysis that P1 exhibited the crystallinity whereas P2 and P3 were amorphous polymers. The glass transition temperature (T _g) determined by DSC and the temperature at 5% weight loss (T _d5) determined by thermogravimetry (TG) were dependent on the substituent at 9-position on fluorene; both orders of T _g and T _d5 were P3 > P2 > P1, indicating the bulkiness of substituent at 9-position of fluorene resulted in the good thermal stability. It is noteworthy that amorphous P3 exhibiting very high T _g of 156 °C and T _d5 of 535 °C is a new heat-resistant polysiloxane derivative as well as a promising candidate for blue-light-emitting materials.     

Effect of feeding astaxanthin with different E/Z-isomer ratios on astaxanthin accumulation in Pacific white shrimp Litopenaeus vannamei

Astaxanthin is traditionally utilized in crustacean aquaculture to enhance the characteristic pink-red color of these species. It has been reported that the bioavailability and body accumulation efficiency of astaxanthin differ based on its E/Z-isomer species, and these trends vary widely among animal species. This study investigated the influences of feeding astaxanthin having different E/Z-isomer proportions on astaxanthin accumulation in Pacific white shrimp Litopenaeus vannamei. Z-Isomer-rich astaxanthin was prepared from the synthetic (all-E)-astaxanthin standard by thermal treatment, and the prepared all-E-isomer-rich astaxanthin pellets (E-AST-P; total Z-isomer proportion = 4.7%) and Z-isomer-rich astaxanthin pellets (Z-AST-P; total Z-isomer proportion of astaxanthin = 81.8%) were fed to L. vannamei for 8 weeks. The feeding of Z-AST-P significantly improved the body astaxanthin concentration compared to those fed the control pellets without adding astaxanthin isomers and E-AST-P; the astaxanthin concentrations after the 8-week treatments of the control pellets, E-AST-P, and Z-AST-P were 7.3 ± 0.5, 6.2 ± 1.8, and 12.3 ± 1.3 µg g^–1, respectively. This result suggested that astaxanthin Z-isomers have higher bioavailability and/or body accumulation efficiency than (all-E)-astaxanthin in L. vannamei. Practical Applications: The bioavailability of astaxanthin is generally very low, which is a critical issue for its use in crustacean aquaculture. In this study, we found that feeding a pellet rich in astaxanthin Z-isomers showed a greater accumulation efficiency of astaxanthin in the whole body of L. vannamei than that fed a pellet rich in the all-E-isomer. Thus, the use of Z-isomer-rich astaxanthin feeds would contribute to improving the quality of crustacean and reducing the feed costs (i.e., reduction of the use amount of astaxanthin).     

Fabrication of stable Al2O3 slurries and dense green bodies using soft-energy milling process

Wet-jet milling and planetary homogenizing processes as soft-energy milling methods were employed as a novel method to prepare stable Al₂O₃ slurries. The viscosity of slurries prepared from the soft-energy milling was constant and stable for long time, as compared to ball-milled slurries. Though Al₂O₃ particles surface after ball milling yielded more hydroxyl groups, Al₂O₃ particles surface after the soft-energy milling was similar state to raw particles surface. Relative density of the green bodies prepared from the wet-milled slurries was about 67% and was independent on the slurry solid content. On the other hand, the relative density of the green bodies prepared from the ball-milled slurries increased with increasing solid content. Linear shrinkage of the sintered bodies prepared from the soft-energy milled slurries was independent of the slurry solid content, whereas that of the sintered bodies prepared from the ball-milled slurries increased with decreasing solid content.     

CHARACTERIZATION OF OSMOTIC DEHYDRATION AND SWELLING OF APPLE TISSUES BY BIOELECTRICAL IMPEDANCE SPECTROSCOPY

The electrical impedance of apple strip samples immersed in osmotic medium was investigated to characterize a dehydration process with sucrose solution and a swelling (hydration) process with deionized distilled water. The impedance measured at frequencies of 10 Hz to 100 kHz could be fitted well by an electrical equivalent model 'Hayden model'. Symplasmic (intracellular) resistance and apoplasmic (extracellular) resistance assumed in the model showed a specific increase or decrease which corresponded to a dehydration or swelling (hydration) process respectively. Consequently, the changes in the resistances were suggested to be caused by an increase or a decrease in moisture content in extracellular and intracellular volumes. Furthermore, the time variation of the resistance values could be represented approximately by a first-order response equation. Therefore, it was concluded that bioelectrical impedance spectroscopy (BIS) was applicable to the simple detection of dehydration and swelling and that it was a helpful and effective method to monitor dehydration and swelling processes nondestructively and continuously.     

Moving shadows contribute to the corridor illusion in a chimpanzee (Pan troglodytes).

Previous studies have reported that backgrounds depicting linear perspective and texture gradients influence relative size discrimination in nonhuman animals (known as the “corridor illusion”), but research has not yet identified the other kinds of depth cues contributing to the corridor illusion. This study examined the effects of linear perspective and shadows on the responses of a chimpanzee (Pan troglodytes) to the corridor illusion. The performance of the chimpanzee was worse when a smaller object was presented at the farther position on a background reflecting a linear perspective, implying that the corridor illusion was replicated in the chimpanzee (Imura, Tomonaga, & Yagi, 2008). The extent of the illusion changed as a function of the position of the shadows cast by the objects only when the shadows were moving in synchrony with the objects. These findings suggest that moving shadows and linear perspective contributed to the corridor illusion in a chimpanzee. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is chimpanzee (Pan troglodytes) spatial attention reflexively triggered by gaze cue?

Humans show a reflexive shift in spatial attention triggered by gaze cues. Chimpanzees (Pan troglodytes) have an excellent ability to follow another's gaze, but they exhibit a limited capacity to engage in triadic interactions based on joint attention, suggesting the possibility of contributions of the different mechanisms underlying joint attention between humans and chimpanzees. The present study thus examined how the chimpanzee's visual spatial attention is triggered by gaze cues. Two chimpanzees showed no clear signs of attention shift triggered by various kinds of nonfacial and facial stimuli with averted gaze under the letter-discrimination tasks but showed significant cueing effects when the head-turning cue was presented in a quasi-dynamic manner. These cueing effects were, however, affected by the predictability of the gaze cue: Highly predictive gaze cues caused stronger cueing effects than less predictive cues. Thus, these results suggest that the shift in spatial attention caused by gaze cues does occur in chimpanzees, but, in contrast to humans, vulnerability against the cue predictability suggests that the voluntary mechanism contributes more dominantly than the reflexive mechanism to this attention shift. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of guidelines for inelastic analysis in design of fast reactor components

The interim guidelines for the application of inelastic analysis to design of fast reactor components were developed. These guidelines are referred from “Elevated Temperature Structural Design Guide for Commercialized Fast Reactor (FDS)”. The basic policies of the guidelines are more rational predictions compared with elastic analysis approach and a guarantee of conservative results for design conditions. The guidelines recommend two kinds of constitutive equations to estimate strains conservatively. They also provide the methods for modeling load histories and estimating fatigue and creep damage based on the results of inelastic analysis. The guidelines were applied to typical design examples and their results were summarized as exemplars to support users.