Challenges to the Carbon Dioxide Capture and Storage (CCS) Technology

Carbon dioxide Capture and Storage (CCS) technology, which is one of the technologies against global warming, applied to the separation and capture of CO₂ gas and finally storage underground is attracting attention. There are several technologies being developed for CO₂ separation and capture, namely the chemical absorption method, physical absorption method, adsorbing separation method and membrane separation method. These are being developed to apply to postcombustion capture, oxyfuel postcombustion capture, etc. With regard to the CO₂ storage technologies, the method of injection into an aquifer is being developed as the major one, and studies on issues for actual technical application are being conducted in the form of engineering study on the assumed model area. In this report, our expectations toward actual application of the CCS technology, the trends of the CCS technology and other related matters are introduced. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Hydrothermal treatment of glycine and adiabatic expansion cooling: implications for prebiotic synthesis of biopolymers

There have been several studies on biopolymer synthesis under hydrothermal conditions. The conventional hydrothermal methods make it possible to synthesize only a dipeptide and short oligopeptides as well as cyclo-dimer, from amino acids. As these studies that were applied with various quenching methods suggested the importance of quenching rate from hydrothermal conditions, rapid quenching could avoid hydrolysis of the oligomers that had already been synthesized under hydrothermal conditions. In this study, therefore, we designed a novel hydrothermal flow reactor adopted with adiabatic expansion cooling system from the reason that it was thought to be one of the most rapid quenching methods. It mimics geysers, fumaroles, hot springs, and volcanic eruptions. Once aqueous solutions of monomers were treated at high temperature and pressure, the solutions were released into the atmosphere through an orifice to be depressurized and cooled down simultaneously with the Joule–Thomson effect. We demonstrated oligomerization of glycine up to decamer (Gly₁₀) by using the flow reactor, which had never been yielded with any other quenching methods. This suggests that rapid quenching methods under non-equilibrium conditions such as adiabatic expansion cooling is an efficient way to produce long oligomers connected by covalent bonds via dehydration condensation.     

MPCP based active optical access network with PLZT high-speed optical switch

An active optical access network architecture with our newly developed PLZT ((Pb,La)(Zr,Ti)O₃) high-speed optical switch is introduced, with a view to realizing the next-generation high capacity scalable access network. This system is developed based on the latest IEEE standard of PON (10G-EPON; IEEE802.3av) in consideration of the coordination with future high capacity PON. PLZT high-speed optical switches are able to switch an optical signal at nano-second speed (<5-10 ns). Generally, the merits of using optical switches are increasing the number of subscribers and transmission distance easily, preventing malicious ONUs from interfacing with the communication between OLT and the other ONUs, realizing fast fiber and OLT protection/restoration and providing various services by controlling optical switches dynamically. This paper focuses on two key technologies; a PLZT optical switch and a new discovery process for active optical access network based on MPCP defined at IEEE802.3. A major challenge in designing active optical access network is supporting the discovery process of MPCP because it does not offer broadcast transmission unlike the regular PON. We propose here a new discovery process; it has been tested successfully in an implementation of our proposed system.     

Basic characteristics of Ar/N2 atmospheric pressure nonequilibrium microwave discharge plasma jets

To understand the mechanism of surface processing by atmospheric pressure nonequilibrium microwave discharge plasma jets of coaxial type without a resonator, we measured the vibrational and rotational temperatures in plasmas using optical emission spectroscopy. The plasma was excited by a microwave power supply, using a gas mixture of Ar and N₂ as the plasma gas, and changing the flow rate of N₂ gas. We also measured the change in the contact angle of a PET film before and after the plasma processing. It decreased as the plasma rotational temperature increased, indicating that the hydrophilicity of the PET surface was improved as the plasma rotational temperature became higher. © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Ozonation of N-Nitrosamines in the Reverse Osmosis Concentrate from Water Recycling Applications

This study aims to evaluate the performance of ozone treatment for removing N-nitrosamines from reverse osmosis (RO) concentrate in water recycling applications. In the absence of any N-nitrosamine precursors, the destruction efficiency of N-nitrosamines was dependent on their molecular weight or the length of the alkyl chain in their molecular structure. Experiments conducted with RO concentrate showed that ozonation could lead to the formation of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), resulting in an increase in concentrations of these N-nitrosamines. Nevertheless, ozonation was effective for destruction of N-nitrosamines with molecular weight greater than that of NDEA (102 g/mol).     

Quantitative measurement of hard x-ray spectra for high intensity laser produced plasma

X-ray line spectra ranging from 17 to 77 keV were quantitatively measured with a Laue spectrometer, composed of a cylindrically curved crystal and a detector. Either a visible CCD detector coupled with a CsI phosphor screen or an imaging plate can be chosen, depending on the signal intensities and exposure times. The absolute sensitivity of the spectrometer system was calibrated using pre-characterized laser-produced x-ray sources and radioisotopes. The integrated reflectivity for the crystal is in good agreement with predictions by an open code for x-ray diffraction. The energy transfer efficiency from incident laser beams to hot electrons, as the energy transfer agency for specific x-ray line emissions, is derived as a consequence of this work.     

用半主动控制悬架改进半挂汽车列车驾驶室的乘坐舒适性

提出加速度阻尼控制新方法，该方法具有传统的阻尼控制方法同等的振动控制效果，而且具有对传感器和控制测量系统的误差不敏感的优点；建立了九自由度半挂汽车列车振动模型，针对半挂汽车列车的驾驶室俯仰振动是影响乘坐舒适性的主要因素的特点，提出了考虑俯仰角振动的加速度阻尼控制方法，计算机模拟计算结果表明，驾驶室的乘坐舒适性得到显著改善。     

Development and irradiation test of lost alpha detection system for ITER

We developed a lost alpha detection system to use in burning plasma experiments. The scintillators of Ag:ZnS and polycrystalline Ce:YAG were designed for a high-temperature environment, and the optical transmission line was designed to transmit from the scintillator to the port plug. The required optical components of lenses and mirrors were irradiated using the fission reactor with the initial result that there was no clear change after the irradiation with a neutron flux of 9.6×10(17)?nm(-2) s(-1) for 48 h. We propose a diagnostic of alpha particle loss, so-called alpha particle induced gamma ray spectroscopy. The initial laboratory test has been carried out by the use of the Ce doped Lu(2)SiO(5) scintillator detector and an Am-Be source to detect the 4.44 MeV high energy gamma ray due to the (9)Be(α,nγ)(12)C reaction.     

Analysis of heat-treated graphite oxide by X-ray photoelectron spectroscopy

X-ray photoelectron spectroscopy (XPS) is among the most powerful methods to determine the surface chemical properties of carbon materials. Because heat-treated graphite oxide includes various defects, analyses of the structure by XPS help us understand the structures of various carbon materials. Thus, XPS spectra of graphene-related materials containing various functional groups and other defects on edges and in the basal plane were simulated and full width at half maximums (FWHMs) and peak shifts were obtained by density functional theory calculation. Shifts of whole C1s spectra were influenced by the electron-withdrawing functional groups such as C=O-containing functional groups. FWHMs of the main peak of C1s spectra were influenced by mainly electron-withdrawing functional groups in addition to defects such as vacancy, pentagons, and heptagons. Analyses using only XPS provide us limited information, even though the peak tops and FHWMs of simulated XPS spectra are used for assignment. Combination use of peak shifts and FWHMs of XPS spectra, infrared spectroscopy, and density functional theory calculation provided more reliable assignments of defects including oxygen-containing functional groups of carbon materials than commonly used methods using only peak shifts of XPS spectra.     

Synthesis of non-equilibrium phases in immiscible metals mechanically mixed by high pressure torsion

The structural changes in mechanically mixed metals of immiscible combinations of elements caused by bulk mechanical alloying (MA) through the use of high pressure torsion (HPT) were investigated in Ag–Ni and Nb–Zr systems. There was no alloying between Ag and Ni on atomic scale even after 100 rotations of HPT. On the other hand, the β-Zr phase started to appear after HPT 2 rotations in the Nb–Zr system, even though β-Zr is a high temperature phase. Further, Nb and Zr were completely mixed to form a bcc structured single phase after HPT 100 rotations. The sequence of alloying in the Nb–Zr system during HPT was discussed. These results clearly suggest that non-equilibrium phases can form in the Nb–Zr system by bulk MA by the use of HPT.