Design and manufacturing of JT-60SA vacuum vessel

JT-60 is planned to be upgraded to JT-60SA tokamak machine with fully superconducting coils, which is a project of the JA-EU satellite tokamak program under both Broader Approach program and Japanese domestic program. The JT-60SA vacuum vessel (VV) has a D-shape poloidal cross section and a toroidal configuration with 10° facet segmented in toroidal direction. The material of the VV is 316L stainless steel with low cobalt content of <0.05 wt%. A double wall structure is adopted for the VV to ensure high rigidity and high toroidal one-turn resistance simultaneously.Fundamental welding R&D and a trial manufacturing of the 20° upper half of the VV have been performed to study the manufacturing procedure. After the confirmation of the quality of the mock-up, manufacturing of the actual VV started in November 2009.     

Present Status of the Nd:YAG Thomson Scattering System Development for Time Evolution Measurement of Plasma Profile on Heliotron J

A new high repetition rate Nd:YAG Thomson scattering system is developed for the Heliotron J helical device.A main purpose of installing the new system is the temporal evolution measurement of a plasma profile for improved confinement physics such as the edge transport barrier (H-mode) or the internal transport barrier of the helical plasma.The system has 25 spatial points with ～10mm resolution.Two high repetition Nd:YAG lasers (>550mJ@ 50Hz) realize the measurement of the time evolution of the plasma profile with ～10ms time intervals.Scattered light is collected by a large concave mirror (D=800 mm,f/2.25) with a solid angle of ～100 mstr and transferred to interference filter polychromators by optical fiber bundles in a staircase form.The signal is amplified by newly designed fast preamplifiers with DC and AC output,which reduces the low frequency background noise.The signals are digitized with a multi-event QDC,fast gated integrators.The data acquisition is performed by a VME-based system operated by the CINOS.     

Thermoelectric Properties of NdGd<Subscript>1+<Emphasis Type="Italic">x</Emphasis></Subscript>S<Subscript>3</Subscript> Prepared by CS<Subscript>2</Subscript> Sulfurization

Ternary rare-earth sulfides NdGd_1+x S₃, where 0 ≤ x ≤ 0.08, were prepared by sulfurizing Ln₂O₃ (Ln = Nd, Gd) with CS₂ gas, followed by reaction sintering. The sintered samples have full density and homogeneous compositions. The Seebeck coefficient, electrical resistivity, and thermal conductivity were measured over the temperature range of 300 K to 950 K. All the sintered samples exhibit a negative Seebeck coefficient. The magnitude of the Seebeck coefficient and the electrical resistivity decrease systematically with increasing Gd content. The thermal conductivity of all the sintered samples is less than 1.9 W K⁻¹ m⁻¹. The highest figure of merit ZT of 0.51 was found in NdGd_1.02S₃ at 950 K.     

Characterizing image quality of autostereoscopic displays by using the maximum luminance at each viewing position

A metric of the 3D image quality of autostereoscopic displays based on optical measurements is proposed. This metric uses each view's luminance contrast, which is defined as the ratio of maximum luminance at each viewing position to total luminance at that position. Conventional metrics of the autostereoscopic display based on crosstalk, which uses “wanted” and “unwanted” lights. However, in case of the multiple‐views‐type autostereoscopic displays, it is difficult to distinguish exactly which lights are wanted lights and which are unwanted lights. This paper assumes that the wanted light has a maximum luminance at the good stereoscopic viewing position, and the unwanted light also has a maximum luminance at the worst pseudo‐stereoscopic viewing position. By using the maximum luminance that is indexed by view number of the autostereoscopic display, the proposed method enables characterizing stereoscopic viewing conditions without using wanted/unwanted light. A 3D image quality metric called “stereo luminance contrast,” the average of both eyes' contrast, is proposed. The effectiveness of the proposed metric is confirmed by the results of optical measurement analyses of different types of autostereoscopic displays, such as the two‐view, scan‐backlight, multi‐view, and integral.     

Control strategies for transients of hydrogen production plant in VHTR cogeneration systems

Operability of Very High Temperature Reactor (VHTR) hydrogen cogeneration systems in response to abnormal transients initiated by the hydrogen production plant is one of the important concerns from economical and safety points of views. The abnormal events in the hydrogen production plant could initiate load changes and induce temperature variations in a primary cooling system. Excessive temperature increase in the primary cooling system would cause reactor scrams since the temperature increase in the primary cooling system is restricted in order to prevent undue thermal stresses from reactor structures. Also, temperature decrease has a potential propagation path for reactor scrams by reactivity insertions as a consequence of the reactivity feedbacks. Since suspensions of reactor operation and electricity generation should be avoided even in case of abnormal events in the hydrogen production plant from an economical point of view, an establishment of a control scheme against abnormal transients of hydrogen production plant is required for plant system design.In the present study, basic controls and their integration for the GTHTR300C, a VHTR cogeneration system designed by JAEA with a direct Brayton cycle power conversion unit and thermochemical Iodine-Sulfur process hydrogen production plant (IS hydrogen production plant), against abnormal transients of IS hydrogen production plant are presented. Transient simulations for selected load change events in the IS hydrogen production plants are performed by an original system analysis code which enables to evaluate major phenomena assumed in process heat exchangers of the IS hydrogen production plant.It is shown that abnormal load change events are successfully simulated by the system analysis code developed. The results demonstrated the technical feasibility of proposed controls for continuous operation of the reactor and power conversion unit against load change events in the IS hydrogen production plant.     

A new position‐sensorless position control method for high‐speed spindle systems

This paper proposes a new position‐sensorless position control method for high‐speed spindle drive systems. Mechanical vulnerability of position sensors such as an encoder mounted on a spindle motor is becoming a serious problem as required speed increases. For high speeds above 1500 rad/s, sensorless drive is preferred. It is possible for current technologies to control spindle motor in speed control mode without the sensor, but not in position control mode without the sensor. In the example of high‐speed spindle systems of automatic machine tools, implements must be automatically attached to and removed from the spindle at standstill. Automation necessitates position control, for which current technologies require a sensor. The proposed method makes it possible to realize pure sensorless high‐speed spindle systems performing in both speed and a position control modes. The method can attain a position control performance with quick settling from speed control and a repetitive positioning precision of 0.006 rad, 0.4°, which is comparable to that achieved by current sensor‐based methods. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(3): 58–69, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10059     

Suppression by carotenoids of microtenoids of microcystin-induced morphological changes in mouse hepatocytes

Microcystin-LR is a liver tumor promoter in the okadaic acid class, a group of potent inhibitors of protein phosphatases 1 and 2A. Because of inhibition of protein phosphatases, microcystin-LR induces hyperphosphorylation of cellular proteins, including cytoskeletal proteins—cytokeratins 8 and 18—and causes morphological changes in mouse hepatocytes in primary culture. We studied the effects of carotenoids to antagonize microcystin-LR-induced morphological changes in hepatocytes. β-Carotene (100 nM to 100 μM), suppressed the morphological changes induced by 100 nM microcystin-LR in a dose-dependent manner. Other carotenoids tested exerted similar suppressive effects, although retinoids, such as all-trans retinol, all-trans retinoic acid, and 9-cis retinoic acid, were only weakly suppressive. The relative potency of the suppression correlated significantly with the number of conjugated double bonds in thetrans configuration. β-Carotene strongly suppressed the hyperphosphorylation of cellular proteins induced by microcystin-LR without significant changes in the basal phosphorylation level. Other antioxidants, such as α-tocopherol, did not protect the cells against microcystin-LR. Taken together, the antagonistic effects of carotenoids against microcystin-LR are difficult to explain by their antioxidant or provitamin A activities. Suppression of the hyperphosphorylation of cellular proteins may be a novel mechanism by which carotenoids inhibit tumor promotion.     

Increase in the expression of biglycan mRNA expression Co-localized closely with that of type I collagen mRNA in the infarct zone after experimentally-induced myocardial infarction in rats

Biglycan, a small dermatan sulphate proteoglycan, has been postulated to interact with other components of the extracellular matrix (ECM), specifically collagens. We hypothesized that biglycan messenger ribonucleic acid (mRNA) is increased in the myocardial infarct zone. Biglycan mRNA expression after acute myocardial infarction (AMI) in rats was determined with the use of Northern blotting and in situ hybridization, and its expression pattern was compared to that of type I collagen mRNA [alpha1(I) collagen]. The left coronary artery was ligated in male Sprague-Dawley rats, and the hearts were excised on days 2 and 7. The Northern blot analysis demonstrated that expression of biglycan mRNA in the infarct on days 2 and 7 were 4.0- and 6.8-fold higher, respectively, compared to the sham-operated hearts. The in situ hybridization revealed intense signals for both biglycan and alpha1(I) collagen mRNA on day 2 in the spindle-shaped mesenchymal cells located between the surviving myocytes in the infarct peripheral zone. On day 7, biglycan mRNA signals were observed in the interior of the infarct around the infarct granulation tissue, a distribution that was essentially the same as that of alpha1(I) collagen. These results demonstrated that the increases in the infarct biglycan mRNA expression produced by mesenchymal cells (presumably myofibroblasts and fibroblasts) was closely co-localized with that of type I collagen mRNA, indicating that biglycan contributes to the infarct healing processes.     

Micromechanical characterization of local deformation in interlaminar-toughened CFRP laminates

The in situ SEM micro-line/grid methods were applied for quantitative evaluation of microscopic deformation in interlaminar-toughened CFRP cross-ply laminates with transverse cracks. Both the local deformation in the interlaminar region around the transverse crack tip and the crack opening displacement (COD) were observed at different temperatures to evaluate the effect of thermal residual stress. A two-dimensional approximate elastic analysis of stress and displacement fields in interlaminar-toughened cross-ply laminates with transverse cracks was conducted and compared with the experimental results. A reasonable agreement was obtained which implied the applicability of the analysis. The analysis will be a basis for the optimal design of interlaminar-toughened composite laminates.     

Electrolyzed-reduced water scavenges active oxygen species and protects DNA from oxidative damage

Active oxygen species or free radicals are considered to cause extensive oxidative damage to biological macromolecules, which brings about a variety of diseases as well as aging. The ideal scavenger for active oxygen should be 'active hydrogen'. 'Active hydrogen' can be produced in reduced water near the cathode during electrolysis of water. Reduced water exhibits high pH, low dissolved oxygen (DO), extremely high dissolved molecular hydrogen (DH), and extremely negative redox potential (RP) values. Strongly electrolyzed-reduced water, as well as ascorbic acid, (+)-catechin and tannic acid, completely scavenged O.-2 produced by the hypoxanthine-xanthine oxidase (HX-XOD) system in sodium phosphate buffer (pH 7.0). The superoxide dismutase (SOD)-like activity of reduced water is stable at 4 degrees C for over a month and was not lost even after neutralization, repeated freezing and melting, deflation with sonication, vigorous mixing, boiling, repeated filtration, or closed autoclaving, but was lost by opened autoclaving or by closed autoclaving in the presence of tungsten trioxide which efficiently adsorbs active atomic hydrogen. Water bubbled with hydrogen gas exhibited low DO, extremely high DH and extremely low RP values, as does reduced water, but it has no SOD-like activity. These results suggest that the SOD-like activity of reduced water is not due to the dissolved molecular hydrogen but due to the dissolved atomic hydrogen (active hydrogen). Although SOD accumulated H2O2 when added to the HX-XOD system, reduced water decreased the amount of H2O2 produced by XOD. Reduced water, as well as catalase and ascorbic acid, could directly scavenge H2O2. Reduce water suppresses single-strand breakage of DNA b active oxygen species produced by the Cu(II)-catalyzed oxidation of ascorbic acid in a dose-dependent manner, suggesting that reduced water can scavenge not only O2.- and H2O2, but also 1O2 and .OH.