Seiichi Suzuki

In situ electrochemical degradation of trichloroethylene (TCE) is one of the promising options for low-cost remediation of TCE. However, actual TCE degradation has not yet been established in our study because of the compound’s volatility and adsorption onto soil surfaces. In this study, degradation of TCE in a model soil by an electrochemical process was confirmed by GC-ECD, TOC, IC, GC-MS, and ion chromatography analyses. The electrochemical degradation was performed in a model soil consisting of glass beads and aqueous solution, and the residual TCE and degradation products were determined. Complete decomposition of TCE to CO2 and chloride ion was achieved by application of a 10 V d.c. voltage.

At some point during acid leaching column tests of heavy metals from municipal waste incinera-tion ash, sudden and rapid elution of harmful elements was observed which was called the breakthrough (BT) phenomena. The mechanism was elucidated from the results of measurement of elemental and particle size distribution in the column and batch leaching tests as follows. At the first stage of experimental runs, CaC03 was dissolved in acidic solution and pH profile along the bed is formed. Some of the minor elements of Zn and A1 dissolved by acid at the upper part of the column are precipitated at bottom of the column, leading to the reduction of flow rate of the leachate solution. After leachate pH becomes low by the termination of dissolution of Ca, these deposits are dissolved and thus, the flow rate increases. Most of the trace elements behave as such, which causes the increase of harmful element concentrations in the eluate. Some drastic concentration increase of harmful elements in leachate may occur even after the long period of pseudo stable dissolution behavior in the land-fill site.

Fluorescence anisotropy of green fluorescent protein (GFP) molecule, immobilized on the surface of quartz substrate as single molecular layer, was measured for application to nano-probing of local environment. GFP has fluorescence without any additional prosthetic group or metal atom. It has protective structure against the outer environment. For use of nano-probe of local environment, fluorescence anisotropy of GFP was measured as it is immobilized on quartz substrate. By comparison with back ground scattering, fluorescence anisotropy of GFP was measured with higher fidelity. The anisotropy value suggests rather free rotational motion of GFP in tethered state on the substrate.

To investigate the environmental dynamics of radioactive cesium (Cs) and strontium (Sr) in farmland in Japan, non-radioactive Cs and Sr were added to field plots and their absorption by pasture crops was examined. The intrinsic Cs absorption capacity of plants was also examined by cultivating them in agar to exclude the possibility of Cs adhering to soil particles. In the field experiment, crop yields decreased when Cs and Sr were added together but did not change significantly when Cs or Sr alone was added. Addition of Cs to the field plot resulted in significantly higher Cs concentration in the crop, while addition of Sr had no such effect. The amount of Cs accumulated by the crop, however, was less than 1% of the amount added to the plot, suggesting that only a limited amount of radioactive Cs from fallout would be translocated to the crop. The agar cultivation test revealed a positive correlation between the growth rate and the Cs content of the crop. The Cs concentration in plants cultivated in agar was closely correlated with that in the field crop. This suggested that Cs absorbed by plants in farmland remained in a free state because K and Ca in soil inhibited its adhesion to soil particles. In conclusion, it was considered that almost all Cs in farmland adhered to soil particles and was not available for adsorption by plants, while a small portion remained in a free, absorbable state due to the effects of nutrient elements.

In our previous studies, CO2 gasification characteristics of char produced by rapid pyrolysis were evaluated for various biomass samples of softwoods and hardwoods, which were pyrolyzed at 1000 degrees C in a small-scale fluidized bed with porous alumina as bed material under N-2 flow (regular gasification). The characteristic curve of conversion rate dX/dt versus conversion obtained from the gas evolution rate revealed a sharp peak the gasification at conversion of around X=0.05 in the case of softwoods, which was suggested to be affected by the bed material. In the present study, the effects of the type of bed material on the gasification characteristics were examined using bed materials of alumina, silica sand and pulverized brick for the gasification of cypress. It was found that the characteristic peak in gasification was observed only with alumina as bed materials. To elucidate the cause of this phenomenon, the char and bed materials were together cooled to room temperature under a nitrogen flow, separated by sieving, and then independently gasified. The char produced in the alumina bed was found to have a low conversion rate, while the alumina bed material was gasified more rapidly and showed the characteristic peak in gasification. While the ratios of hydrogen production to carbon monoxide production in the gasification of separated char and bed materials were always lower than those of regular gasification, the decrease in the case of char gasification was much greater than in the case of bed materials. The decrease in the ratio in the gasification of char was the biggest for alumina followed by brick, while the decrease in the gasification of bed materials was the smallest for alumina and the largest for silica sand. The present results indicate that the reactive carbonaceous material with high hydrogen content was easily moved to alumina and hold, which showed rapid gasification at the first stage of gasification.

<p>Ocean Thermal Energy Conversion (OTEC) is widely expected to be highly practical technology, largely for the reasons of using inexhaustible renewable energy and continuous electricity generation under any weather conditions. One point to be considered in OTEC is the cost of electricity generation, of which a large portion is found to be accounted for the cost of water intake facilities by the analyses of the report for demonstration plant at Kumejima. In this paper, we examined the cost in various settings, including water intake facilities optimization. Against the power generation cost 120.5 yen/kWh at 1,250 kW scale of Kumejima demonstration plant (the intake facilities in business, without the grant), is reduced to 50.5 yen/kWh by optimization of individual components including water intake facilities, and is further reduced to 43.4 yen/kWh by integrating water intake pipes to one pipe. The present findings indicate that an optimized OTEC system will be sufficiently cost competitive against a small scale diesel generator in a small island. Though it is required to further reduce the cost of power generation for the full-scale dissemination of OTEC, there is a limit in the current state of the water intake and power generation technologies under the constraint of the surface water temperature. There is a need to consider economies of scale and the form and effect of the high-temperature side heat source auxiliary equipment.</p>

Sustainable carbon fixation system with large scale afforestation in arid land has been proposed for the mitigation of global warming. To avoid the problem of rainfall shortage and the large evaporation loss, our afforestation system has adopted a water-harvesting system. We have set a research site near Leonora (mean annual rainfall and evaporation are about 200 mm and 2,500 mm, respectively), Western Australia. We have so far developed an original runoff simulation model for understanding of water behavior involving penetration, evaporation and runoff. In previous studies, the best values of corrective coefficient of penetration (PR), and equivalent roughness coefficient (N) were determined by fitting numerical results to the water level data of the collecting pond of a watershed within 6 km × 4.8 km. In the present paper we extend this model to the larger area of 43 km × 52 km to evaluate the change in water penetration before and after the afforestation of bare ground, assuming that penetration rate of the bare ground changes to that of woodland by the afforestation. Then we evaluate effect of afforestation on penetration water amount by comparing the calculated results before and after afforestation in the large area. Finally we show the strategy to select appropriate afforestation sites and the way to evaluate the effects of afforestation on the vegetation of the peripheral areas.

The biodiesel derived from animal fats has the problem of high Cold Filter Plugging Point (CFPP, an index of the low temperature property). Therefore, the pyrolysis method has been paid attention to. In this method, the ester bond of triglyceride, the principal ingredient of oils and fats, is cracked by the decarboxylation reaction. As a result, the biodiesel consist of hydrocarbons is produced and its CFPP is lower than that of conventional biodiese. Authors have so far clarified the following two facts. The decarboxylation occurs to triglyceride after it is converted to fatty acid. The Pd-loaded active carbon is effective for the promotion of the decarboxylation of the fatty acid. However, Pd is expensive. Therefore, cheap Ni catalysts were tested in this report. As a result, it was clarified that the Ni-loaded brown coal is effective for the promotion of the decarboxylation of fatty acid.

A high definition immunosensor for antigen and nonspecific protein was developed. Immunosensor has been studied for decades as highly sensitive and specific sensor device against any of the antigen materials. However no solid device has successfully discriminated the target antigen in mixture solution of nonspecific proteins. This is simply because large amount of physical adsorption of nonspecific molecule intervenes the specific detection of antigen molecule. In this study, fluorescence anisotropy measurement method is employed for direct monitoring of antibody molecule motion, and antigen antibody binding was detected with no interference of nonspecific adsorption. With spot antibody immobilization technique, simultaneous multi-channel detection was demonstrated, with sensitivity of fg/mL.

Thermal decomposition experiments of woody wastes contaminated with radioactive materials were conducted using an externally-heated horizontal kiln in the work area for segregation of disaster wastes at Hirono Town, Futaba County, Fukushima Prefecture. Radioactivity was not detected in gaseous products of thermal decomposition at 923 K and 1123 K a after passage through a trap filled with activated carbon. The contents of radioactive cesium (Cs-134 and Cs-137) were measured in the solid and liquid products of the thermal decomposition experiments and in the residues in the kiln after all of the experiments. Although a trace amount of radioactive cesium was found in the washing trap during the start-up period of operation at 923 K, most of the cesium remained in the char, including the residues in the kiln. These results suggest that most of the radioactive cesium is trapped in char particles and is not emitted in gaseous form.

Pressure drop and transfer rate of wood powder pellets were measured using a cold model of a horizontally rotating cylinder with two pairs of internal screw cylinders. The transfer rate was one order of magnitude smaller than that when the pellets are moved along by a screw movement, which indicates their flow over the central shaft of screw cylinders. Using internal cylinders of simple design, the operational range showing good gas-solid contact was narrow. Modification of the internal cylinders with partial cover of the entrance sides allowed high packing of pellets with good gas-solid contact and stable pressure drop.

Immunosensor utilizes antibody as receptor of biological molecules. For it’s high sensitivity and specificity to the target molecule, it is expected for quick diagnosis of infective diseases. In spite of intensive efforts for development, however, practical use of immunosensor is yet to be realized for low S/N ratio by the surface adsorption of non-specific molecules. In this study, high S/N ratio sensing scheme was developed through fluorescence anisotropy measurement. Antigen-antibody binding is detected as molecular motion change without disturbance of surface adsorption. Fluorescent labeled antibody was immobilized on a quartz substrate and anisotropy change by administration of antigen was measured. Fluorescence anisotropy changes of 9 specimens were among 0.03-0.06. Antigen binding was confirmed even with existence of 10 μg /mL BSA.

In this study, high separation ratio microfluidic cell sorting by a dielectrophoretic (DEP) force is presented. The recent development of iPS cell technology has raised the possibility of regenerative therapy. Technologies of genetic cell processing require purification of specific target cells by a cell sorter. The most widely used system for cell separation is flow cytometry (FCM), which has been developed for research purposes. Despite the excellent separation ratio it achieves, it has a rather high cost per operation. For clinical use, devices contacting biological specimens must be disposable to prevent cross-infection. A low cost microfluidic cell sorter, using the DEP force, can be fabricated by photolithography. However, the sorting rate of existing DEP cell sorters is far lower than that of FCM because of limitations of the applicable voltage in an aqueous fluid. To circumvent the problem and raise the DEP force, the implementation of field gradient dependence was investigated. The flow channel was designed to produce a high gradient at the separation point and to enhance the DEP force. Numerical calculations by the finite element method indicate that the electric field distribution has a peak intensity at the entrance to the separation channel. DEP separation of latex beads 2 m in diameter at a flow speed of 3.0 mm/s, six times that of our previous system, was demonstrated.

Immunosensor is an ideal kind of biosensor, which enables highly specific detection of any kind of biological molecules. However, in spite of long and intensive efforts of research and development, no immunosensor is in practical use. This is mainly because of the difficulty in reduction of the back ground noise of non-specific adsorption. In this study, fluorescence anisotropy decay principle was employed to avoide the disturbance of non-specific adsorption. Fluorescent labeled antibody, with Pyrene derivative, was immobilized on the surface of quartz substrate. Fluorescence anisotropy of immobilized antibody was measured by evanescent excitation stage. Antigen solution was administrated on the surface of the substrate and antigen antibody binding was detected as fluorescence anisotropy change. Detection of antigen at the concentration of as low as 100 fg/mL was demonstrated.

Jatropha (family-Euphorbiaceae) is a genus of approximately 175 succulent plants, shrubs, and trees. Jatropha seeds have 25-40% oil content. In India, it is being promoted as a biofuel crop and as a means to alleviate poverty. Women's self-help groups are promoting Jatropha to small farmers by capitalizing on a microcredit system. The life-cycle analysis (LCA) developed for this study was carried out in a typical arid area, Panna (India), considering Jatropha cultivation on wasteland, poor agricultural land, and sparsely planted forest land. Block-wise data for land use patterns, land cover, and agricultural resources/practices were collected. The LCA of Jatropha oil processed via transesterification as well as direct mixing with diesel fuel was carried out, and a comparative analysis was undertaken vis-a-vis bio-oil from agricultural biomass (BTL (Ag)) under different cultivation conditions. The investigation's scope included reductions in CO2 emissions and economic returns to farmers. The resulting analysis is presented taking into consideration, globalization and subsidized fossil fuel supplies.

Biomass has been recognized as a renewable energy source alternative to fossil fuels, because it doesn't increase CO2 amount in the atmosphere. Among various ways of woody biomass use, IGCC power generation is known as the most possibly efficient technology. In the process, biomass is firstly pyrolyzed and the produced volatile and char are secondary converted hence it is necessary to know the production process and yields of pyrolysis gas, tar, producing char and char gasification kinetics for effective energy conversion. In this study, many woody biomass species (four softwoods, nine hardwoods and four barks) were pyrolyzed at 1000 °C at the rapid heating rate up to around 1000 °C /s. Then the produced char is gasified in an experimental fluidized bed. After that, the produced char was gasified by CO2 at 1000°C. We computed char conversion and its rate from CO production rate with time and conversion rate was plotted against conversion. Different gasification rate curves are found for various biomass samples. The gasification rate of char was evaluated by the first order rate constant based on the volume reaction model. Hardwood char gasification rates were faster than those of softwood samples. Most of the gasification rates of char from the bark samples were nearly same as those of woody part samples. As for the hardwood, the char produced from biomass with lower compressive strength generally gave faster reaction rate.

A versatile method of measuring electro-optic coefficients (r(ij) : i = 4-6 and j = 1-3) of isometric, uniaxial, and biaxial crystals without crystal coordinate rotation has been developed. It has been confirmed theoretically and experimentally that the change in the retardation of an X-cut Y-propagation LiNbO3 crystal depends on the square of the electric field along the X-direction. The constant stress electro-optic coefficient r(51) of the LiNbO3 crystal is found to be 32.05 +/- 0.01 pm/V at 632.8 nm. (c) 2013 The Japan Society of Applied Physics

Fluorescence anisotropy of GFP molecules, suspended in solution and immobilized on a glass substrate, was measured to investigate the application for nano-environment probe. Nano-environment around living cell is of interest in relation with wide range of fields, such as cell interaction in cancer tissue, nerve signal transmission and so on. However, nano-environment is so sensitive to the interference of probe or measurement itself. For example, measurement of neuron potential is performed by inserting electrode to the tissue, or staining with toxic dye. For measurement of nano-environment GFP has some superior characteristics. GFP molecule itself is soluble protein and has little toxicity to the cell. It need no prosthetic group for fluorescent activity, and easily introduced by genetic method. We investigated the fluorescence anisotropy of GFP for probing molecular motion in the nano space. Anisotropy of free molecule in solution was compatible with theoretical value. Immobilized molecule, on the contrary, showed higher anisotropy than theoretically expected. This extraordinary value may come from hydrophobic interaction of GFP with glass surface, that can be utilized for nano-probing.

The blood test is a routine procedure in medical diagnosis. However it takes a couple of days to get the results because blood samples are analyzed by sending to the specialized facility because the operation of the blood test instrument is costly for a hospital or clinic. So development of a novel low cost blood test device is an important issue considering the burden of the patient. To developing a low cost and instant diagnosis system, various immunosensor have been studied because of it's quick response and application of micro fabrication. But background noise by the surface adsorption reduces the S/N ratio, and practical use of the immunosensor isn't possible for now. So we tried to detect antigen-antibody reaction by fluorescence anisotropy in this study. Fluorescence anisotropy retains the information of the rotational motion of antibody molecules. As the antigen bounds to the antibody, the degrees of rotational freedom are reduced and the antigen-antibody reaction can be detected by the shift of fluorescence anisotropy. In principle fluorescence anisotropy is not affected by the nonspecific surface adsorption. A micro optical immunosensor was fabricated. Detection of anisotropy change by the antigen-antibody reaction was demonstrated with the device. For higher S/N ratio observation, evanescent excitation system was also developed.

The purpose of this study is the development of a medical cell sorter. Cell sorters that are currently used were developed for research, but they have problems of high running cost or risk of infection in medicine. Here, we reduce operating costs by using a photolithography technique. This cell sorter uses dielectropllOretic force to act on non-charged particles in a non-uniform electric field, and the force increases in proportion to the gradient of the square of the field intensity. We utilized the stronger dielectrophoretic forces to act on cells by raising an electric field that was confined through applying a voltage to the solution of the complex dielectric constant, which was smaller than the surrounding wall, and therefore narrowed the shape of the fractionation. We confirmed that this cell sorter gave the slope of the probability of 27.8%. As a result, we showed that dielectrophoresis in this cell sorter could be used to distribute non-charged particles.

In this study, a high separation ratio micro-fluidic cell sorting by dielectrophoretic (DEP) force is presented. Resent development of iPS cell technology has promoted the possibility of regenerative therapy. In technologies of genetic cell processing requires purification of specific target cells by cell sorter. Most prevailing system for cell separation is the flow cytometry (FCM), which has been developed for research purpose. In spite of the high performance in separation ratio, it takes rather high cost in one operation. For clinical use, a device contacting biological specimen must be disposable to prevent cross infection. A low cost micro-fluidic cell sorter, using DEP force, can be fabricated by photolithography technique. However, sorting rate of existing DEP cell sorter is far lower than that of FCM because of the limitation of applicable voltage in aqueous fluid. To circumvent the problem and raise the DEP force, implementation of field gradient dependence was investigated. The design of flow channel was deiced to make high gradient at the separation point, and enhance the DEP force. Distribution of the electric field was proved to have a peak intensity at the entrance of separation channel by numerical calculated of Finite Element Method. DEP separation of 2μm diameter latex beads at the rate of 3.0mm/sec, 6 times large than that of our previous system, was demonstrated. © 2012 The Institute of Electrical Engineers of Japan.