Chemical composition and microstructure of Al3BC3 prepared by different densification methods

“Al₈B₄C₇” and Al₃BC₃ powders were synthesized, and the formation of secondary phases was suppressed during the densification of the ternary aluminum borocarbides. The so-called “Al₈B₄C₇” was Al₃BC₃ containing excess Al and B. The excess components in “Al₈B₄C₇” promoted the densification of Al₃BC₃. The formation of secondary phases could not be controlled when using the reactive hot pressing method during the densification of Al₃BC₃. In contrast, monolithic Al₃BC₃ was obtained by separating calcination and hot pressing stage. The hardness, Young's modulus and fracture toughness of the sintered Al₃BC₃ were 13.9 GPa, 136 GPa and 2.2 MPa m^1/2, respectively.     

Dynamic friction property and mechanism of line‐type thermoplastic polymer materials for new optical wiring technology

We have been developing a new optical wiring technology for installing indoor optical fiber cables directly into apartment houses for fiber to the home. The technology must minimize the friction of optical fiber cable. We reviewed many studies on friction behavior, and studied the friction properties of a wide variety of polymer sheets and optical fiber cables, and considered the friction mechanism. Relatively, soft polymer materials exhibited stick‐slip behavior and the hard polymers exhibited constant slip behavior. Lubricants are effective in reducing friction and play a dominant role as regards the friction property. Silicon and fluorocarbon agents play some role in converting the stick‐slip characteristic into constant slip behavior. A certain roughness is effective in reducing friction. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers.     

Upgrading the NIFS superconductor test facility for JT-60SA cable-in-conduit conductors

The superconductor test facility at the National Institute for Fusion Science (NIFS) was upgraded to test cable-in-conduit (CIC) conductors for the JT-60SA equilibrium field (EF) coil. Supercritical helium (SHe) lines were assembled with transfer tubes and a heat exchanger. The CIC conductor was covered with a thermal insulation vessel, filled with gas helium at atmospheric pressure. The temperature of the conductor was varied using a film heater attached to an inlet pipe. Critical current (Ic) and current sharing temperature (Tcs) measurements of the prototype CIC conductor were carried out successfully in the upgraded test facility. During the measurements, the conductor temperature was precisely controlled.     

Can environmental investment and expenditure enhance financial performance of US electric utility firms under the clean air act amendment of 1990?

This study investigates the causality from environmental investment (as a long-term effort) and expenditure (as a short-term effort) to financial performance in the US electric utility industry. The industry is one of the large air polluters in the United States. This empirical study finds that the environmental expenditure under the US Clean Air Act has had a negative impact from 1989 to 2001. The negative impact has become much effective after the implementation of the Title IV Program (1995) of the US Clean Air Act. This study cannot find the influence of environmental investment on financial performance by a statistical test although it indicates a positive impact. In the United States, fossil-fueled power plants such as coal-fired ones still produce a large portion of electricity. The generation structure is inconsistent with the betterment in the US environmental protection and imposes a financial burden to electric utility firms.     

Crystal quality of InN thin films grown on ZnO substrate by radio-frequency molecular beam epitaxy

The growth of InN on {0001} ZnO substrates by radio-frequency, plasma-assisted, molecular-beam epitaxy (RF-MBE) has been experimentally investigated. The reflection high-energy electron diffraction (RHEED) pattern quickly recovered to a 1×1 streak pattern as the InN growth was started on nitridated ZnO substrates, whereas the RHEED pattern of the ZnO substrate was spotty because of plasma damage induced by nitridation. The full width at half maximum (FWHM) of the (0002) InN rocking curve was estimated to be around 150 arcsec from x-ray diffraction (XRD). Furthermore, we observed a remarkable feature from our experiments; namely, the crystal quality of InN does not seem to depend on the surface polarity of the ZnO substrate, while it is well known that InN growth on GaN has strong polarity dependence. To investigate this tendency, we have also investigated the surface stability of adatoms, In and N, on Zn- and O-face ZnO surfaces using a first-principles technique. From the theoretical study, N adsorption is more stable on ZnO surfaces of both polarities compared with In adsorption. Accordingly, the preferential initiation by N adatoms onto both ZnO surfaces can explain the unique style of InN growth on ZnO substrates.     

A fast market splitting matching method for the spot electric power market

A fast, innovative matching method for the spot power market, considering network constraints, has been developed. In this method, buy and sell order bids are respectively divided into the aggregated volume of several band prices. Then, the aggregated volume and the center of each band price are used to calculate an index band clearing price, which contains the real clearing price. The division and calculation process is iterated until the band price is less than the tick size of the bidding price. This method is applied to a real problem in the Japan power market, with 9 bidding areas, 10 area‐connecting lines, and 9000 orders (volume/price pairs). Numerical simulation results show that the new method is ten times faster than conventional linear programming, demonstrating the effectiveness of this method. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(4): 21–29, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20694     

Charge storage mechanism of nanostructured anhydrous and hydrous ruthenium-based oxides

The charge storage mechanism of nanostructured anhydrous and hydrous ruthenium-based oxides was evaluated by various electrochemical techniques (cyclic voltammety, hydrodynamic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy). The effects of various factors, such as particle size, hydrous state, and structure, on the pseudocapacitive property were characterized. The electric double layer capacitance (C_dl), adsorption related charge (C_ad), and the irreversible redox related charge (C_irr) per unit mass and surface area of electrode material has been estimated and the role of structural water within the material either in micropores or interlayer are discussed.     

A study of the mineralogical alteration of bentonite in saline water

The mineralogical alteration of bentonite was studied in saline water at 60 and 90 °C. To obtain the altered bentonite, a crude bentonite (Kunigel V1) was dispersed into simulated sea-water, and maintained at 60 or 90 °C over 6000 h. Magnesium was accumulated into bentonite during the experiments at levels over the cation exchange capacity (CEC; 0.78 meq/g for the original bentonite) at only 90 °C. The excess Mg was not replaced by ammonium ions, suggesting that the precipitation of Mg solid in bentonite occurred. The IR spectra and the thermogravimetric/differential Thermal Analysis (TG-DTA) profiles show the neo-formation of magnesium hydroxide in the altered bentonite. The CEC decreased from 0.78 to 0.45 meq/g as the amount of accumulated Mg increased. The distribution coefficient K_d for Cs in the altered bentonite was half of that in the original bentonite. It is conjectured that the thermal alteration of bentonite in saline water affects the sorption capacity of Cs onto smectite.     

Neutron-capture cross-sections of 244Cm and 246Cm measured with an array of large germanium detectors in the ANNRI at J-PARC/MLF

The neutron neutron-capture cross cross-sections of ²⁴⁴Cm and ²⁴⁶Cm were measured by the time-of-flight method in the energy range of 1–300 300 eV with an array of large germanium detectors in the Accurate Neutron-Nucleus Reaction measurement InstrumentANNRI at Material and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research ComplexJ-PARC/MLF. The ²⁴⁴Cm resonances at around 7.7 and 16.8 8 eV and the ²⁴⁶Cm resonances at around 4.3 and 15.3 3 eV were observed in the capture reactions for the first time. The uncertainties of the obtained cross cross-sections are 5.8% at the top of the first resonance of ²⁴⁴Cm and 6.6% at that of ²⁴⁶Cm. The rResonance analyses were performed for low-energy ones using the code SAMMY. The prompt γ-ray spectra of ²⁴⁴Cm and ²⁴⁶Cm were also obtained. Eight and five new prompt γ-ray emissions were observed in the ²⁴⁴Cm(n, γ) and ²⁴⁶Cm(n, γ) reactions, respectively.     

Analysis of cesium isotope compositions in environmental samples by thermal ionization mass spectrometry – 1. A preliminary study for source analysis of radioactive contamination in Fukushima prefecture

Cesium was recovered from plant samples obtained from Fukushima prefecture. The isotopic ratios of ¹³⁴Cs/¹³⁷Cs and ¹³⁵Cs/¹³⁷Cs were analyzed by thermal ionization mass spectrometry with a single filament method using a TaO activator. Samples containing 5 Bq of ¹³⁷Cs were analyzed with typical analytical errors of approximately 0.5% for ¹³⁴Cs/¹³⁷Cs and approximately 0.1% for ¹³⁵Cs/¹³⁷Cs. Measurements of both ratios showed profiles that were characteristic of the measurements of among other environmental samples reported in the literature. The results showed the isotopic ratios of ¹³⁴Cs/¹³⁷Cs and ¹³⁵Cs/¹³⁷Cs were applicable for the source analysis of radioactive Cs in Fukushima prefecture.