Structural characterization of photoreduced complete and incomplete cubane-type molybdenum oxide clusters in CO and their catalytic behavior in propene metathesis reaction

SiO2-impregnated complete and incomplete cubane-type molybdenum oxide clusters such as [(RhCp*)₄Mo₄O₁₆] (I) and [(RhCp*)₂Mo₃O₉(OMe)₄] (II) were photoreduced with a UHP-Hg lamp (> 365 nm) in CO, resulting in the formation of catalytically active species for propene metathesis at 300 K. The CO-photoreduced Mo oxide clusters were characterized by EXAFS, IR, XPS and TPD technique. The results suggest that the Mo-O_4c (four-centered bridging oxygens) in I were specifically reduced with CO under the illumination to produce two sets of subcarbonyl species, e.g., those characteristic of the IR bands at 2061 and 2021 cm^–1, which were thermally inactive for the¹³CO exchange reaction but very active under illumination at 300 K, possibly assignable to Mo(CO)x (x = 2, 3), whereas those at 2092 and 2035 cm^–1 due to Rh(CO)₂, which were readily exchangeable with¹³CO at 300 K in dark. Removal of both carbonyls attached on Rh and Mo in photoreduced I and II by evacuation at 375–440 K led to the formation of oxygen-deficient Mo⁴+/Mo⁵⁺ sites, which exhibited high catalytic activities in propene metathesis at 300 K to produce an equimolar mixture of ethene and 2-butenes. The CO-photoreduced incomplete cubane Mo oxide cluster (II) exhibited higher activities and higher trans/cis ratios of 2-butenes in the reaction, compared with those on the photoreduced I.     

The effect of lutein supplementation on visual fatigue: A psychophysiological analysis

We used psychophysiological technology to examine the effect of an oral supplement, a combination of lutein, zeaxanthin and blackcurrant extract (LUT), on visual fatigue, within the context of a randomized, double-blind, placebo-controlled cross-over trial. The LUT supplement and placebo samples were randomly assigned to thirteen participants, who took the samples for two LUT (and vice versa) for another 2 week. Each participant completed visual proof reading tasks for 2 h during each of four testing sessions. Saccade tests were administered before and after the proof reading task, during which the participants moved their eyes back and forth between two targets positioned in the center of two checkerboards. We recorded EEG, EOG, heart rate, and facial muscle potential/performance during the saccade tests. Blood pressure was measured and subjective fatigue and stress scores were collected before and after the proof reading task. We averaged EEG starting at saccade offset in order to analyze eye fixation related potentials (EFRP). Our results suggested that the proof reading task induced visual fatigue. An analysis of EFRP and other psychophysiological data revealed significant differences between the LUT and placebo conditions. These results suggest that supplementation with LUT could help to reduce symptoms of visual fatigue.     

Microstructural Design of Silicon Nitride with Improved Fracture Toughness: II, Effects of Yttria and Alumina Additives

Significant improvements in the fracture resistance of self-reinforced silicon nitride ceramics have been obtained by tailoring the chemistry of the intergranular amorphous phase. First, the overall microstructure of the material was controlled by incorporation of a fixed amount of elongated ß-Si₃N₄ seeds into the starting powder to regulate the size and fraction of the large reinforcing grains. With controlled microstructures, the interfacial debond strength between the reinforcement and the intergranular glass was optimized by varying the yttria-to-alumina ratio in the sintering additives. It was found that the steady-state fracture toughness value of these silicon nitrides increased with the Y:Al ratio of the oxide additives. The increased toughness was accompanied by a steeply rising R -curve and extensive interfacial debonding between the elongated ß-Si₃N₄ grains and the intergranular glassy phase. Microstructural analyses indicate that the different fracture behavior is related to the Al (and O) content in the ß´-SiAlON growth layer formed on the elongated ß-Si₃N₄ grains during densification. The results imply that the interfacial bond strength is a function of the extent of Al and Si bonding with N and O in the adjoining phases with an abrupt structural/chemical interface achieved by reducing the Al concentration in both the intergranular phase and the ß´-SiAlON growth layer. Analytical modeling revealed that the residual thermal expansion mismatch stress is not a dominant influence on the interfacial fracture behavior when a distinct ß´-SiAlON growth layer forms. It is concluded that the fracture resistance of self-reinforced silicon nitrides can be improved by optimizing the sintering additives employed.     

Advanced grid connected PV system with functions to suppress disturbance by PV output variation and customer load change

The PV array has unstable output patterns dependent on weather conditions. Therefore, assuming high-density grid connection in the future, these unstable output patterns can be one of the main reasons to cause power disturbances such as the voltage variation, the frequency variation and the harmonic voltage generation into utility. And also it should be considered that a sudden customer load change is one of those reasons. Therefore, this study suggested a PV system with suppression functions against such disturbances in the side of amicable relationship with utility and verified the validity of the proposed system by EMTP and ACSL-based analysis.     

Contact force detection on a minute aperture mounted optical contact slider using an acoustic emission sensor

Advances in the digital network society require both higher density and higher transfer rates in all sorts of storage systems. Especially in optical recording, the trend toward higher density and larger capacity requires novel surface-recording technologies that can drastically diminish head-to-medium spacing, resulting in an improvement in spatial resolution and, finally, a higher recording density. To this end, we have already proposed a novel contact optical head slider that is able to almost cancel the suspension load by generating hydrodynamic pressure, thus realizing a lower net contact force. Evaluating the dynamic contact force is requisite in realizing its stable sliding operation and higher signal readout performance. In this study, a continuous acoustic emission (AE) signal was utilized to detect the dynamic contact force. AE signal modulation was compared with the applied out-of-plane acceleration on a medium generated by a spindle combined piezo-electric actuator. It was clarified that the detected AE modulation amplitude was approximately proportional to the applied acceleration, and that utilizing AE modulation will be a useful method for evaluating dynamic contact force.     

Antihypertensive Effect of Salt-Free Soy Sauce,a New Fermented Seasoning,in Spontaneously Hypertensive Rats

ABSTRACT: In this study, we focused on the antihypertensive effect of newly fermented salt-free soy sauce (SFS) in spontaneously hypertensive rats (SHRs). A 13-wk oral administration of SFS was performed daily in 8- to 21-wk-old SHRs with a dose of 200 mg/kg of body weight/d. The systolic (SBP) and diastolic (DBP) blood pressures were measured for each week during the experimental period. As a result, a significant (P < 0.01) BP lowering effect was observed from the 5th d to the end of the experiment in the SFS group compared with the control group (ΔSBP_21-wk: 27 mmHg, ΔDBP_21-wk: 20 mmHg). In contrast to such substantial effect by SFS intake, angiotensin I-converting enzyme activities in blood and local organs as well as pharmaceutical parameters such as serum Na⁺ or K⁺ level did not show any significant difference between in both SFS and control groups. Vasoconstriction experiment using thoracic aorta rings from 21-wk SHRs provided an interesting result that the rings from the SFS group evoked a >2-fold higher increase in the angiotensin II-stimulated constrictive response compared with the rings from the control group (P = 0.012), which suggested that the SFS-intake would be effective in possessing a higher vessel tone. Practical Application: In this study, we investigated the antihypertensive effect of newly fermented SFS in SHRs. As a result of 13-wk SFS-administration, we found a significant antihypertensive effect of the SFS. This finding strongly demonstrates that the developed SFS would be greatly beneficial for health and useful for health-related industries.     

Application of a novel polypropylene to the insulation of an electric power cable

Cross‐linked polyethylene (XLPE) has been widely adopted as insulating material for high‐voltage power cables up to 500 kV. Further improvement of electrical and thermal properties on insulating material is required in order to increase cable operation efficiency. Therefore, the development of novel insulating material possessing high thermal properties will be necessary. Recent progress of catalysis technology contributes to obtain new polymeric materials which may be applied to electrical insulation. The authors investigated the basic properties of newly developed stereoregular syndiotactic polypropylene (s‐PP) which is synthesized with homogeneous metallocene catalyst. Though recycling of cross‐linked polymers such as conventionally used XLPE may be difficult because of their poor heat deformation, the s‐PP which is not cross‐linked must be suitable for recycling. A series of experiments on its physical and electrical properties gave the following results.

• (1) s‐PP has sufficient flexibility compared with isotactic polypropylene (i‐PP ).
• (2) Both AC and lightning impulse breakdown strength of s‐PP in spite of no cross‐linking are superior to those of XLPE in the temperature range from 25 to 90 °C.
• (3) Degradation by copper of s‐PP is less than that of i‐PP.
• (4) s‐PP/VLDPE blend shows sufficient brittleness temperature for use.

These results suggested that s‐PP should serve as insulating material for power cables at higher‐temperature operation. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 18–26, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002//eej.10210     

Numerical simulation of critical current performance in Nb3Sn strand subjected to periodic bending deformation

In the ITER Engineering Design Activity (EDA), four NB₃Sn model coils were developed and successfully tested. However, it was revealed that the critical current of the conductor degraded with the increase of electromagnetic force. One of the explanations of this phenomenon is a strand bending caused by enormous electromagnetic force. The authors therefore developed a simulation code using the distributed circuit model to investigate dependency of the critical current performance on the periodic bending deformation. The simulation results were in good agreement with the experiments. The dependence of the critical current on the periodic transverse load, temperature, periodic load pitch, thickness of Ta barrier which prevents Cu stabilizer from being contaminated by Sn, twist pitch of the strand, and RRR of the bronze matrix was investigated using the developed code. The results showed that the critical current degraded less with decreasing the pitch of the transverse load and increasing the Ta barrier thickness. It suggests that the shorter cabling pitch and the larger bending stiffness prevent the critical current degradation. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(3): 7–15, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20923     

Anti‐Sway Crane Control Considering Wind Disturbance and Container Mass

A method for estimating the sway angle using an observer has already been proposed. The state observer estimates the sway angle accurately and must use the detected sway angle value. However, the estimated sway angle has an error owing to rope length error, friction force, and wind. Moreover, the container mass cannot be determined, and therefore the observer parameter is not suitable. We already proposed robust antisway control for overcoming rope length error without adding a new sensor. Further, we designed a friction disturbance observer to cancel out the influence of the friction force. In this paper, we first propose a container mass estimation method when a crane system performs rolling up control. The observer parameter can be selected using the estimated mass value. Second, in crane parallel shift control, we propose a robust antisway control even when there is a wind disturbance. We design a wind disturbance observer and propose a wind disturbance estimator to separate the friction observer output from the wind disturbance observer output. We confirm through experiments that the proposed method can reduce vibration.