Isolation and characterization of novel lipases from a metagenomic library of the microbial community in the pitcher fluid of the carnivorous plant Nepenthes hybrida

Members of the genus Nepenthes are carnivorous plants that use the pitfall method of insect capture as a supplementary nutritional source. We extracted metagenomic DNA from the microbial community found in the pitcher fluid of Nepenthes and constructed a plasmid-based metagenomic library. An activity-based screening method enabled the isolation of two lipase genes, lip1 and lip2. Both Lip1 and Lip2 belong to a novel family or subfamily of lipases and show lipase activities in acidic conditions, such as those found in pitcher fluid. This study was conducted under the assumption that the secreted Lip1 and Lip2 were capable of enzymatic activity in the acidic pitcher fluid.     

Evaluation tests of 1700 °C class turbine cooled blades for a hydrogen fueled combustion turbine system

The development of 1700 °C class hydrogen fueled combustion turbine system with output of 500 MW and thermal efficiency of over 60% (HHV) has been conducted in the World Energy Network (WE‐NET) program. This paper describes the development of the first‐stage turbine cooled stator and rotor blades applied to the power generation system. The conceptual design of these cooling blades which were served in hot steam flow was carried out. The hybrid cooling method combining recovery cooling with partial ejection cooling was chosen from several cooling systems from a viewpoint of plant efficiency, operational reliability, and durability of cooled blades. Also, the single crystal superalloy (SC) as a blade substrate and thermal barrier coating (TBC) were applied. The experiments of the scale model turbine cooled blades were carried out using a hydrogen–oxygen combustion wind tunnel with practical steam conditions of 1700 °C and 2.5 MPa. The cooling effectiveness and metal temperature at rated condition and the soundness of TBC and blade substrate of the first stage stator and rotor test blades were clarified. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(3): 237–252, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10088     

Interaction between Barium Titanate and Binary Glasses

Interactions between BaTiO₃, and three binary glasses were studied through the reaction of BaTiO₃, powder with glass powder. For PbO–B₂O₃ and PbO–SiO₂ glasses, the reaction led to stable compound formation, the substitution of Pb in the BaTiO₃ structure, and noticeable grain growth of BaTiO₃. The interaction phenomena for these two glass systems were very similar. The substitution of Pb into BaTiO₃ is assisted by chemical reactions in which BaB₂O₄ or Ba₂SiO₄ is formed. The substitution into BaTiO3 also seems to be closely related to the grain growth of BaTiO₃. On the other hand, only compound formation was observed during the processing of BaTiO₃ with Bi₂O₃–B₂O₃ glass. Neither BaTiO₃ grain growth nor Bi substitution took place with the Bi₂O₃–B₂O₃ glass system. Based on the observed reactions and the glass viscosity, several sintering aids for BaTiO₃ ceramic products are suggested in this paper.     

High precision in Raman frequency achieved using real-time calibration with a neon emission line: application to three-dimensional stress mapping observations

A three-dimensional (3D) Raman mapping system with a real-time calibration function was developed for detecting stress distributions in solid materials from subtle frequency shifts in Raman spectra. An atomic emission line of neon at 918.3 cm(-1) when excited at 514.5 nm was used as a wavenumber standard. An emission spectrum of neon and a Raman spectrum from a sample were introduced into a single polychromator using a bifurcated optical fiber. These two spectra were recorded simultaneously on a charge-coupled device (CCD) detector using double-track mode. Energy deviation induced by the fluctuation of laboratory temperature, etc., was removed effectively using the neon emission line. High stability during long measurements was achieved. By applying curve fitting, positions of the Raman line were determined with precision of about 0.05 cm(-1). The present system was applied to measurements of residual pressure around mineral inclusions in a natural diamond: 3D stress mapping was achieved.     

Extraction of β–glucan by hydrothermal liquidization of barley grain in a semi-batch reactor

Subcritical water is a natural and green way for extraction of plant biomass components. Here, subcritical water was employed as a media to extract β–glucan from barley (Hordeum vulgare L.) at 130–170°C and 10 MPa. MALDI TOF–MS revealed that main massed peaks of water soluble products were distributed at 500-2900 m/z with a peak to peak mass difference of 162 m/z, consistent with the repeating unit of β–glucan. At 170°C, all amount of water soluble β–glucan has been extracted. Next, the liquid fraction products were atomized directly to produce microsphere particles.     

Carbon nanocomposites synthesized by high-energy mechanical milling of graphite and magnesium for hydrogen storage

Nanocomposites obtained by mechanical milling of graphite and magnesium with organic additives (benzene, cyclohexene or cyclohexane) have been studied with the aim of preparing novel hydrogen storage materials. The organic additives were very important in the milling processes to determine the characteristics of the resulting carbon nanocomposites. The mechanical milling with high energy resulted in the generation of large amounts of dangling carbon bonds in graphite with simultaneous decomposition of graphite structure. Such dangling bonds of carbon acted as sites to take up hydrogen. It has been proved by temperature programmed desorption (TPD) and neutron diffraction measurements that the hydrogen taken up in the nanocomposites exists in at least two states; in the form of C–H bond formation in the graphite component and in the form of hydride in the magnesium component. The relative amounts of two types of hydrogen strongly depended upon differences in additives used (benzene, cyclohexene or cyclohexane). When C₆D₆ besides C₆H₆ was used as additive, the hydrogen taken up was discussed from the standpoint of isotope effects. Upon addition of titanium tetraisopropoxide, the features of hydrogen uptake by the nanocomposites changed completely.     

Effect on Electrical Properties of Barium and Strontium Additions in the Lead Lanthanum Zirconate Stannate Titanate System

The effect of barium (Ba) and strontium (Sr) additions on the electrical properties of lead lanthanum zirconate stannate titanate (PLZST) ceramics and their electrically induced phase change behavior was examined. Sr additions decreased both the ferroelectric (FE) ↔ antiferroelectric (AFE) transition temperature ( T_AFE-FE ) and the temperature of the maximum dielectric constant ( T_MAX ). This indicates that Sr additions stabilize the AFE phase. Along with B-site modifications Sr additions can be used to decrease the switching field and hysteresis. Ba additions caused the temperature range of the AFE phase to narrow by increasing T_AFE-FE and decreasing T_MAX . This behavior indicates an ability to lower the switching field and suppress hysteresis. Using a combination of both A-site and B-site modifications it is possible to tailor the properties (for example, switching field, hysteresis, and operating temperature range) of this group of phase change materials to meet the requirements of specific applications.