Sodium fluorescein (uranine) has been used frequently in tracer tests that carried out in order to monitor recirculating fluids utilized for heat exchange with artificial geothermal reservoir such as hot dry rock geothermal system. It is known that fluorescein decomposes in high temperature condition. In the case which tracer solution contained fluorescein is diluted to around 0.1 mg/l of fluorescein concentration by mixing with existing natural geothermal brine in the underground, fluorescein may be strongly affected by thermal effect. In spite of being relatively short residence time, the recirculating fluid utilized in hot dry rock geothermal system is used under the condition in which the temperature dramatically changes. Therefore it is important to understand the detailed thermal decomposition characteristic of fluorescein.
In this study, the experiments for thermal decomposition of fluorescein were carried out using flow-type reactor, and the effects of the initial concentration of fluorescein and temperature on the thermal decomposition behavior of fluorescein were examined experimentally and kinetically. It was found that the proportion of decomposed fluorescein to the starting became higher as the initial fluorescein concentration became lower. The kinetics of the thermal decomposition of fluorescein was approximately regarded as first-order from the results in our experiments. On the other hand, the rate equation for thermal decomposition of fluorescein should contain the term of the dissolved oxygen concentration, because the oxidation reaction is greatly related to the decomposition of fluorescein. Therefore, the effect of the dissolved oxygen concentration on thermal decomposition of fluorescein was introduced as the term of the abundance ratio of dissolved oxygen for fluorescein in the rate equation. That also means that the influence of the initial fluorescein concentration on the thermal decomposition of fluorescein is represented as the initial abundance ratio of fluorescein for dissolved oxygen. Then the new kinetics on thermal decomposition of fluorescein was suggested considering the initial concentrations of fluorescein and dissolved oxygen.

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Concrete or mortar is one of the fragile materials that possess low tensile strength and relatively high compressive strength. The addition of fibers randomly distributed in the matrix, substantially improves their mechanical performance such as post-cracking strength in compression, strength/toughness (energy required up to failure) in bending, impact strength, fatigue strength and also wear resistance. Fiber reinforced concrete/mortar (FRC/FRM) had been gaining various application fields; tunnel support, dam site, river facilities, road pavement and floor in building.
In this study, uniaxial tension tests of steel/PET fiber reinforced mortar (SFRM/PET-FRM) were conducted by servo-controlled testing machine to obtain stress-displacement curves. The experimental results can be summarized;
1) After mortar was cracked, stress induced by pullout resistance of fibers was observed.
2) The displacement of PET-FRM at which stress took the post-cracking peak value (post-cracking strength) was considerably larger than that of SFRM.
3) The stress/force-displacement curves of SFRM/PET-FRM can be estimated by the results of a single steel/PET fiber pullout tests.
4) As far as SFRM is concerned, the number of fibers observed on the fractured surface is smaller than that on mechanically sectioned surface. In case of PET-FRM, no difference is found in the number of fibers between the fractured and the sectioned surface.

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Authors have continued to study the landscape evaluation of quarry using a still picture as change stimulus. However, there is a possibility where the point that influences the evaluation is not reflected in the still picture. Besides, a reality and a presence are lacked in the still picture because it has not a depth feeling by the movement parallax.
Then, in consideration of daily life and continuousness, the viewpoints feared in the landscape evaluation were specified by the rating scale method that used the video movie from the car window. In addition, the movie simulation that gave the cover planting was made. Evaluation experiment was done by semantic differential method using this movie simulation as change stimulus.
As a result, it became clear that there was a difference of the evaluation structure between the still picture and the movie in the landscape evaluation. The effectiveness of movie simulation was confirmed, and the problem also became clear.

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In the transportation system using a large scaled dump truck, it is important to replace a wheel safely, quickly and easily when a wheel is burst or too much abraded partially. Conventionally, wheel replacement work has been depended on the replacement machinery for exclusive use. Considerable amount of expenditure was necessary to purchase the replacement machinery for exclusive use. Because of this reason, development of wheel replacing unit (handler unit ) has been expected for holding down the production cost.
In this study, motion of a wheel replacement handler was analyzed both theoretically and experimentally, then handler unit was developed and wheel replacement test was carried out. Results obtained from the study are as follows; 1) Optional height of the axis of the large diameter wheel which is to be replaced can be adjusted easily, applying the analyzed equation obtained from theoretical study on the link motion. 2) It was found that a large scale wheel supported by a pair of steel pipes of which diameter and weight were 3.6 m and 5.2 t respectively could be rolled for setting the bolt holes to the bolt positions, when the pipe diameter was larger than 4 in. 3) As a result of rolling test for a large scale wheel using a pair of steel pipes of which diameter were 7in, it was proved that setting work of bolt holes to the bolt positions could be done within the time of 14-20 min. 4) Conclusively, it can be said that the handler unit newly developed in this study has the wide applicability, simplicity and cost performance comparing with conventional wheel replacing machinery.

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Fundamental study to remove sulfur from PbS was performed by heating PbS under a stream of air at a given temperature between 973 K and 1273 K. Desulfurization ratio was evaluated by measuring the amount of SO₂ generated by oxidation reaction and the residual products were analyzed by X-ray diffraction method.
The desulfurization ratio increased with increasing temperature and reached approximately 80 % at 1200 K after 7.2 ks under an air flow rate of 500ml/min. The residual products changed from PbSO₄ to PbO through PbSO₄·xPbO during heating, where X in PbSO₄·xPbO increased with increasing temperature.
SiO₂ was added to PbS to promote desulfurization ratio. Mixtures of PbS and SiO₂ at various ratios were put under a stream of air at the same experimental condition. At 1073 K, SiO₂ showed a remarkable effect on desulfurization at x_sio2 < 0.5, where x_sio2 denotes mole fraction of SiO₂ in PbO-SiO₂ system. At x_sio2 = 0.3, the desulfurization ratio was approximately 80 % which is equal to the value of the case at 1173 K without SiO₂.

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Removal of selenium compound, especially hexavalent selenate ion, is one of the most difficult water treatment techniques and an effective method has not yet been established. In this research we propose a novel selenium removal process called Recycled Green rust/Ferrite Process, composed of an addition of Fe source, an alkaline conditioning of a concentrated slurry, an anaerobic chemical reaction stage, and a return of the settled slurry after solid-liquid separation. A mixed Fe²⁺-Fe³⁺ hydroxide compound, green rust (GR), reduces selenate to elemental selenium, while GR is consequently oxidized to magnetite Fe₃O₄. Therefore the black-colored magnetic slurry containing GR and magnetite contributes to the removal of selenate. Repeated batch-mode selenium removal tests showed that the residual selenium concentration gradually decreased with the number of batch test increased. Addition of ferrous sulfate or ferrous chloride (resulting Fe²⁺ concentration 600 mg/L) was eligible for Fe source for GR formation. Stable selenium removal was achieved when the number of batch test exceed 15 times. Optimum selenium removal ratio reached 99.95% where initial Se concentration 2.1mg/L decreased to 0.001mg/L. In contrast, little Se removal occurred when the combination of ferrous sulfate and elemental iron powder (each Fe²⁺ and Fe⁰ concentration was 300 mg/L) was used. During the reaction, oxidation-reduction potential leveled off -700mV vs Ag/AgCl and no dissolved oxygen was detected, indicating a strong reducing condition suitable for the reduction of selenate. Ninety percent of selenium disappeared as soon as the GR formed, and then selenate removal rate followed a first-order kinetics depending on the slurry concentration. These experimental results indicated that the proposed process served an advanced treatment technique for selenate-contaminated water.

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