On-line monitoring system of P5CDF homologues in waste incineration plants using VUV-SPI-IT-TOFMS

It usuallytakes a few weeks to analyze dioxin concentrations and dioxin-TEQ (toxicity equivalency quantity) in fluegases from municipal solid waste (MSW) incinerators by a standard method provided by Japanese industrial standard (JIS 0311). To reduce the required time for analysis, we have developed a new on-line measuring system for furans homologues. This system is composed of a sensitive and robust vacuum ultraviolet (VUV) single-photon ionization (SPI) ion trap (IT) time-of-flight mass spectrometer (VUV-SPI-IT-TOFMS) and automatic sampling/concentrating process. In this work, pentachloro-dibenzofuran (P5CDF) was selected as an index homologue in chlorinated dibenzo-p-dioxin/ furan homologues (DXNs) because its concentration and I-TEF (international toxicity equivalency factor), which are 2,3,4,7,8-P5CDF is 0.5 and 1,2,3,7,8-P5CDF is 0.05, are high and the concentration correlates closely with the total amount of dioxin-TEQ. The lowest detectable limit, 1 pg (0.001 ng-TEQ/m3 N) was demonstrated by laboratory tests. This system underwent a field test at several actual MSW plants and the tests revealed the following: (a) This system is applicable for dioxin-TEQ evaluation from actual MSW incinerators. (b) It can continuously monitor P5CDF in a fluegas for 7 months. (c) The frequency of the measurements is once every 2-6 h, depending on the concentration of P5-CDF.     

Spring bloom in a hypereutrophic lake, Lake Kasumigaura, Japan—V : Factors controlling natural population of phytoplankters

Temperature was the limiting factor controlling the multiplication rate and standing stock of natural population density of phytoplankters in the lake of Tsuchiura Harbor during the spring bloom of 1980. The temperature relationship of the multiplication rate could be expressed as an Arrhenius equation during the spring bloom. The species composition of the natural phytoplankton community, on the other hand, was affected chiefly by combination of the ambient nutrient concentrations of ammonium, nitrate, phosphate and silicate. Although many phytoplankton species occurred, one temperature relationship appeared to hold for mixed species of the natural community from 4.4 to 24.9° C.     

Automatic ship berthing using artificial neural network trained by consistent teaching data using nonlinear programming method

Ship handling during berthing is considered as one of the most sophisticated tasks that a ship master has to face. The presence of current and wind make it even more complicated to execute, especially when ship approaches to a pier in low speed. To deal with such phenomenon, only experienced human brain decides the necessary action taken depending on situation demand. So automation in berthing is still far beyond imagination. But, if the human brain can be replicated by any suitable artificial intelligence technique to perform the same action that human brain does during berthing, then automatic ship berthing is possible. In this research artificial neural network is used for that purpose. To enhance its learnability, consistent teaching data based on the virtual window concept are created to ensure optimal steering with the help of nonlinear programming language (NPL) method. Then instead of centralized controller, two separate feed forward neural networks are trained using Lavenberg–Marquardt algorithm in backpropagation technique for command rudder angle and propeller revolution output respectively. The trained ANNs are then verified for their workability in no wind condition. On the other hand, separate ANNs are trained with reconstructed teaching data considering gust wind disturbances. To deal with any abrupt condition, ANN followed by PD controller is also introduced in case of command rudder angle output whose effectiveness is well verified not only for teaching data but also in case of non-teaching data and different gust wind distributions.     

Synthesis of Magnetically Intensified Aluminosilicate

Intensification of magnetic susceptibility of the zeolite ensures not only quick and reliable separation of the zeolite from waste medium by using a magnetic separation but also efficient micro-wave heating of the zeolite.Thus,reinforcement of magnetic susceptibility of the zeolite has been attempted.In this study,a composite material has been synthesized by adding magnetite during a synthesis process of the zeolite.And the composite was evaluated by using XRD and SEM.It was composed of zeolite and magnetite.And,its shape was polygonal with a few micrometers size under the synthesis time of 4 weeks.Its magnetization in magnitude was about 400 times larger than that of the normally synthesized zeolite.And the mass ratio of the zeolite and the magnetite in the synthesized material was estimated at about 7.8:1.     

Structure and properties of Ti(IV)-doped zinc hydroxychloride rusts formed at various temperatures

To simulate the atmospheric corrosion of steels galvanized with Ti–Zn alloys under different atmospheric temperatures, Ti(IV)-doped zinc hydroxychloride (Zn₅(OH)₈Cl₂·H₂O: ZHC) was prepared at various aging temperatures of 6–120 °C. Adding the Ti(IV) inhibited the crystallization and particle growth of ZHC, showing a minimum at 50 °C. Higher aging temperature promoted the formation of TiO₂ nano-particles. Elevating the aging temperature suppressed the adsorption of H₂O and CO₂ on Ti(IV)-doped ZHC. These results suggest that the alloying Ti in galvanized steel forms compact zinc rust layer at various atmospheric temperatures in marine environment, which would lead to the enhancement of corrosion resistance.     

Etching of metallic materials with Cl2 gas cluster ion beam

Cluster ion beam processes exhibit high rate sputtering with low damage, and in particular, extremely high sputtering rates are expected using reactive cluster ion beams. Si could be sputtered at extremely high rates using reactive cluster ion beams, such as SF₆, Cl₂, CF₄, CHF₃, and CH₂F₂. However, processing of metallic materials with reactive cluster ion beams has not been studied yet. It was expected that high-speed etching of metallic materials can be realized with Cl₂ cluster ion irradiation, because such a beam would reactively sputter these materials. We generated a Cl₂ cluster ion beam and investigated the etching characteristics of various metallic materials, such as Ni and Al films, under this irradiation. The size of the Cl₂ cluster, as measured with a time-of-flight (TOF) system, was about 1400 molecules. The sputtering yield for each metal was more than 10 times higher than that obtained with Ar cluster ions, showing that Cl₂ cluster ion irradiation reactively sputtered the metallic materials. These results indicated that Cl₂ cluster ion irradiation was suitable for high-speed processing of metallic materials.     

Effects of Microstructure and Composition on the Curie Temperature of Lead Barium Niobate Solid Solutions

The Curie temperature of normally sintered and hot-pressed Pb_1-xBa _x Nb₂O₆ ( x = 0.30, 0.37, 0.41, and 0.50) was dependent on the sample preparation conditions. Samples with large amounts of pores and cracks had higher Curie temperatures than dense samples. Dense samples with fine grains had higher Curie temperatures than those with coarse grains. Comparison between microstructure and the Curie temperature revealed that the variation in Curie temperature was caused by internal stresses developed in the paraelectric-to-ferroelectric phase transition. Large internal stresses increased the free energy of the ferroelectric phase, and thus decreased the Curie temperature. The magnitude of internal stresses depended on the microstructure. Pores and cracks relaxed internal stresses, resulting in high Curie temperatures. Grain boundaries also relaxed internal stresses; samples with small grains had high Curie temperatures. Furthermore, the magnitude of internal stresses was dependent on the crystal structure of ferroelectric phases; samples with the tetragonal ferroelectric structure had internal stresses larger than those with the orthorhombic ferroelectric structure. The effect of crystal structure was discussed in terms of the relaxation of internal stresses by the formation of 90° domains     

Pulsed wire discharge apparatus for mass production of copper nanopowders

A pulsed wire discharge (PWD) apparatus for the mass production of nanopowders has been developed. The apparatus has a continuous wire feeder, which is operated in synchronization with a discharging circuit. The apparatus is designed for operation at a maximum repetition rate of 1.4 Hz at a stored energy of 160 J. In the present study, Cu nanopowder was synthesized using the PWD apparatus and the performance of the apparatus was examined. Cu nanopowder of 2.0 g quantity was prepared in N(2) gas at 100 kPa for 90 s. The particle size distribution of the Cu nanopowder was analyzed by transmission electron microscopy and the mean surface diameter was determined to be 65 nm. The ratio of the production mass of the powder to input energy was 362 g/kW h.     

Estimation of the contribution of ultrafine particles to lung deposition of particle-bound mutagens in the atmosphere

The present study was performed to estimate the contributions of fine and ultrafine particles to the lung deposition of particle-bound mutagens in the atmosphere. This is the first estimation of the respiratory deposition of atmospheric particle-bound mutagens. Direct and S9-mediated mutagenicity of size-fractionated particulate matter (PM) collected at roadside and suburban sites was determined by the Ames test using Salmonella typhimurium strain TA98. Regional deposition efficiencies in the human respiratory tract of direct and S9-mediated mutagens in each size fraction were calculated using the LUDEP computer-based model. The model calculations showed that about 95% of the lung deposition of inhaled mutagens is caused by fine particles for both roadside and suburban atmospheres. Importantly, ultrafine particles were shown to contribute to the deposition of mutagens in the alveolar region of the lung by as much as 29% (+ S9) and 26% (−S9) for the roadside atmosphere and 11% (+ S9) and 13% (−S9) for the suburban atmosphere, although ultrafine particles contribute very little to the PM mass concentration. These results indicated that ultrafine particles play an important role as carriers of mutagens into the lung.