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Objective: The handover of vehicle control from automated to manual operation is a critical aspect of interaction between drivers and automated driving systems (ADS). In some cases, it is possible that the ADS may fail to detect an object. In this event, the driver must be aware of the situation and resume control of the vehicle without assistance from the system. Consequently, the driver must fulfill the following 2 main roles while driving: (1) monitor the vehicle trajectory and surrounding traffic environment and (2) actively take over vehicle control if the driver identifies a potential issue along the trajectory. An effective human-machine interface (HMI) is required that enables the driver to fulfill these roles. This article proposes an HMI that constantly indicates the future position of the vehicle. Methods: This research used the Toyota Dynamic Driving Simulator to evaluate the effect of the proposed HMI and compares the proposed HMI with an HMI that notifies the driver when the vehicle trajectory changes. A total of 48 test subjects were divided into 2 groups of 24: One group used the HMI that constantly indicated the future position of the vehicle and the other group used the HMI that provided information when the vehicle trajectory changed. The following instructions were given to the test subjects: (1) to not hold the steering wheel and to allow the vehicle to drive itself, (2) to constantly monitor the surrounding traffic environment because the functions of the ADS are limited, and (3) to take over driving if necessary. The driving simulator experiments were composed of an initial 10-min acclimatization period and a 10-min evaluation period. Approximately 10 min after the start of the evaluation period, a scenario occurred in which the ADS failed to detect an object on the vehicle trajectory, potentially resulting in a collision if the driver did not actively take over control and manually avoid the object. Results: The collision avoidance rate of the HMI that constantly indicated the future position of the vehicle was higher than that of the HMI that notified the driver of trajectory changes, χ2 = 6.38, P < .05. The steering wheel hands-on and steering override timings were also faster with the proposed HMI (t test; P < .05). Conclusions: This research confirmed that constantly indicating the position of the vehicle several seconds in the future facilitates active driver intervention when an ADS is in operation.

The intramolecular dehydrogenative cyclization of 2-(dialkylsilyl)biaryls proceeded in the presence of a catalytic amount of platinum(II) chloride and potassium tris(3,5-dimethyl-1-pyrazolyl)borohydride to give good yields of the corresponding dibenzosilole derivatives.

The vegetables grown in the two different fields 60 and 230km apart from the Fukushima Daiichi Nuclear Power Plant accident were examined after the accident to determine the concentration of {sup 134}Cs, {sup 137}Cs and {sup 40}K together with those of soil. For the edible part, the transfer of {sup 134}Cs and {sup 137}Cs was observed to potato tuber only in the field of about 60km apart from Fukushima Daiichi Nuclear Power Plant. The contamination of radioactive caesium({sup 134}Cs+{sup 137}Cs)was less than 7Bq/kg-wet weight in tuber and that of soil was less than or equal to 1235Bq/kg-dry weight. As to the edible part of cabbage and lettuce grown in each field, the concentration of {sup 134}Cs and {sup 137}Cs was less than the detection limit. The concentration of soil in each field was 651Bq/kg-dry weight or less. The concentration of {sup 40}K of each field was nearly constant in vertical direction, however that of {sup 134}Cs and {sup 137}Cs showed the vertical distribution of which the highest concentration was observed at soil surface. (author)

Glutamate dehydrogenase (GDH) catalyzes the reversible amination of 2-oxoglutarate with ammonium to form glutamate. GDH functions in nitrogen assimilation in microorganisms, such as Aspergillus nidulans. However, in plants, glutamine synthetase, not GDH, carries out nitrogen assimilation. Here, we report the eects of introduction of the gdhA gene, encoding NADP(H)-dependent glutamate dehydrogenase, from A. nidulans into potato. We analyzed the r esulting changes of photosynthesis, biomass, carbon and nitrogen contents under control and low-nitrogen conditions at theowering stage and the tuber-bulking stage. �ere were higher NADP(H)-GDH activities in GDH potato leaves than in the wild type. Regardless of nitrogen conditions, photosynthetic rates and soluble protein concentrations of leaves increased in GDH potatoes at theowering stage. High photosynthetic rates remained at the tuber-bulking stage in GDH potatoes. �e number and dry weight of tubers also increased in GDH potatoes. Under the low-nitrogen condition in particular, carbon and nitrogen contents of GDH potato tubers increased compared with those of the wild type. �is resulted from hig her rates of carbon and nitrogen redistribution to tuber in GDH potatoes than in wild-type potatoes. Ourndings show that the gdhA gene is a powerful tool to increase tuber dry matter and improve eciency of nitrogen use of potato.

福島原子力発電所から約230km離れた，東京都西東京市における研究圃場において原発事故後に栽培された野菜及び土壌の，134Csと137Csの放射能を測定した。試料は植え付け47日後のジャガイモの葉，並びに，苗の定植40日後のキャベツの外葉を用いた。両者共，134Csと137Csの総量は9Bq/kg以下となり，摂取制限に関する指標値500Bq/kgより低い値であった。土壌は約130Bq/kgであり，天然の40Kの約290Bq/kgと比較しても低い値であった。キャベツの外葉を水で洗浄する前後の放射能像をイメージングプレートにより得たが変化は見られなかった。

A simple, low-cost capillary electrophoresis-mass spectrometry (CE-MS) method is demonstrated for the simultaneous analysis of amino acids and small carboxylic acids (glycerate, lactate, fumarate, succinate, malate, tartrate, citrate, iso-citrate, cis-aconitate, and shikimate). All CE-MS experiments were performed using a single uncoated fused-silica capillary and with a single separation electrolyte, formic acid. For CE polarity, the CE inlet was set as the anode, and the MS side was set as the cathode. By using high-speed sheath gas flow, the apparent mobilities of all compounds were sped up; thus, the migration times of the carboxylic acids were reduced. In positive ion mode ESI-MS detection, small carboxylic acids were detected faintly as m/z = [M + 18](+) or [M + 23](+), after protonated molecule detection (m/z = [M + 1](+)) of the amino acids. In negative ion mode, all of these small carboxylic acids were detected clearly as deprotonated molecules (m/z = [M - 1](-)), after detection of the amino acids. By changing the polarity of the MS during CE separation, both amino acids and small carboxylic acids were detectable in a single electrophoresis analysis run. With this method, the diurnal metabolic changes of pineapple leaves were observed as reflecting Crassulacean acid metabolism.

On the Loess Plateau, China, several planted tree species such as Populus hopeinsis and Robinia pseudoacacia suffer occasional diebacks in the top shoots, reducing growth rates after maturation. However, this does not usually occur in other species, e.g., Ulmus pumila and Zizyphus jujuba . We compared stable carbon isotope ratios ( δ 13 C) as indicators of leaf water-use efficiency (WUE), leaf mass per unit area (LMA), and leaf area- and mass-based nitrogen content (N area and N mass ) by tree height (1, 5, and 10 m) in P. hopeinsis , R. pseudoacacia , U. pumila , and Z. jujuba . In P. hopeinsis and R. pseudoacacia , leaf δ 13 C and N area were significantly lower in 10-m trees than in 1-m saplings, indicating that leaf WUE and photosynthetic rates of both species decreased with tree height. In contrast, δ 13 C in Z. jujuba varied little with tree height. The δ 13 C of 10-m-tall U. pumila trees was significantly higher than that of 1-m plants, demonstrating an increase in WUE with tree height. Decreasing WUE, leaf N area , and N mass with height increases in P. hopeinsis and R. pseudoacacia may be related to water and nutrient limitations for these species in semiarid regions. In contrast, stable or increasing δ 13 C with tree height in U. pumila and Z. jujuba may account (to some extent) for successful production of these species under identical environmental conditions. Diameter growth rate also decreased with maturity in P. hopeinsis and R. pseudoacacia , but increased or was stable for U. pumila and Z. jujuba . The differences in leaf WUE and LMA among species with tree maturity may be related to species’ growth patterns and susceptibility to drought stress, and are likely to be important new criteria for plantation species selection on the Loess Plateau.

A 13 C pulse-labeling experiment was conducted under ambient CO2 and free-air CO2 enrichment (FACE) conditions to understand how elevated CO2 affects the CH4 in soil bubbles and CH4 emissions from rice paddies. Two hills of rice plants enclosed by frames in ambient CO2 and FACE plots were labeled with 13 CO2 at the panicle formation stage, and plants and soil bubbles were collected 2 and 51 days after the pulse labeling. CH4 and 13 CH4 emissions were also measured by the closed-chamber method between the 2 bubble samplings. Conversion of photosynthate carbon to CH4 entrapped in soil bubbles and CH4 emission to the atmosphere occurred quickly, suggesting that recent photosynthates can be an important source of carbon for methanogenesis. About 1% of the 13 C-labeled C taken up through photosynthesis was emitted as 13 CH4 during the 7 weeks of measurement, most during the first 3 weeks after labeling. Total CH4 and 13 CH4 emissions did not differ between the ambient CO2 and FACE treatments, because the entra...

Increasing global atmospheric CO2 concentrations are expected to influence crop production. To investigate the effect on rice (Oryza sativa L.), plants were grown under ambient CO2 (AMB) or free-air CO2-enrichment (FACE) at CO2 concentrations ranged from 275 to 365 μmol mol−1 above AMB. We supplied 13CO2 to the plants at different growth stages so we could examine the contribution of carbohydrate stored during the vegetative stage or newly fixed carbohydrate produced during the grain-filling stage to ear weight at grain maturity. In plants supplied with 13C at the panicle-initiation or pre-heading stages, plants grown under FACE had more starch in the stems at heading, but there was no difference in stem 13C content. Furthermore, there were no differences between treatments in whole-plant 13C contents at heading and grain maturity. In contrast, plants supplied with 13C at the grain-filling stage had more 13C in the whole plant and the ears at grain maturity under FACE than under AMB, indicating that the increased amount of photosynthate produced at the grain-filling stage under CO2 enrichment might be effectively stored in the grains. Furthermore, regardless of when the 13C was supplied, plants had more 13C in starch in the ears at grain maturity under FACE than under AMB. Therefore, CO2 enrichment appears to promote partitioning of photosynthate produced during both vegetative and grain-filling stages to the grains.

Grain filling of rice (Oryza sativa L.) is thought to be affected not only by the supply of carbohydrate from source organs, but also by sink activity, including the activities of enzymes related in starch synthesis. To examine the effect of translocated carbohydrate on sink activity, we cultured detached ears (cut 7 days after flowering) in a solution containing sucrose at various concentrations, glutamine and vitamins. Grain weights 16 days after the start of ear culture increased with increasing sucrose concentration up to 50-70 g sucrose l -1 , but not above this range, probably because of low water potential. Activities of ADP glucose pyrophosphorylase, soluble starch synthase and sucrose synthase rapidly decreased in grains grown without sucrose, but increased with increasing sucrose concentration up to 50-70 g l -1 . Expression of mRNAs for these enzymes and for sucrose transporter was also generally increased by sucrose at 50-70 g l -1 . Though there was a good correlation between activity and expression of mRNA for sucrose synthase, the correlation for other enzymes was not very good. Thus, we suggested that the sink activity of grains in rice ears, and therefore the grain filling, was affected by the supply of carbohydrate from source organs, and that it was also owing to factors other than transcriptional regulation.

In rice, caryopses located at the base of the panicle have a lower growth rate than those at the tip of the panicle. The former and latter types of caryopses are called inferior and superior caryopses, respectively. Taking the different growth rate into consideration, sugar status and the expression of genes encoding carbohydrate-metabolizing enzymes in inferior caryopses were compared with those in superior caryopses. During the first 5 d after flowering, superior caryopses elongated rapidly, but inferior caryopses did not. At this phase, inferior caryopses had a low ratio of hexose to sucrose, high activity of acid invertase and the absence of the expression of the genes encoding the above enzymes except for two isoforms of cell wall invertase, OsCIN4 and INV1, in comparison with superior caryopses. At the start of caryopsis elongation in both superior and inferior caryopses, the hexose/sucrose ratio increased accompanied by gene expression of vacuolar invertase (INV3), sucrose synthase (RSus1) and ADP-glucose pyrophosphorylase (AGP-L2: D50317). Furthermore, the genes related to endospermal starch accumulation were expressed highly with the decrease in the hexose/sucrose ratio after its peak. Based on the comparison of superior and inferior caryopses, the possible mechanism of grain filling in rice is discussed.

Here, we propose new improvement targets capable of decreasing loss of the sturdiness of the lower part in the rice plant (Oryza sativa L.), thereby improving lodging resistance. In nine rice cultivars with various plant lengths, we analyzed the factors responsible for sturdiness of the lower part and, thus, for resistance to lodging. The ratio of lodging resistance to sturdiness of the lower part (RLS) was calculated. The difference in pushing resistance between the lower part and the whole plant varied among cultivars. Among the morphological traits, plant length and the weight of the upper part of plant were not correlated with RLS, but the difference between plant length and length from the ground to the ear (DPE), as well as the weight of the lower stem, were positively correlated with RLS. DPE and the weight of the lower stem were not significantly correlated with ear weight. These results suggest that improvements in DPE and in the weight of the lower stem could be primary targets for improving RLS, thus increasing lodging resistance, without affecting yield.

Carbohydrate contents varied with position in a leaf sheath, and differed between the flag leaf sheath and the second leaf sheath below the flag leaf (-2 leaf sheath) in rice (Oryza sativa L.). In the -2 leaf sheath before heading, light microscopy revealed differences in the distribution of starch granules depending on position. Leaf sheaths were divided into several parts, and the contents of carbohydrates (starch, sucrose, and hexoses) were measured in each part. Before heading, the content of accumulated starch increased linearly from the top to the bottom in -2 leaf sheaths (r2=0.99, P

The relation between the uptake of atmospheric CO(2) and insect's production of silk fiber has not yet been reported. Here, we provide the first quantitative demonstrations that four species of silkworms (Bombyx mori, Samia cynthia ricini, Antheraea pernyi, and Antheraea yamamai) and a silk-producing spider (Nephila clavata) incorporate atmospheric CO(2) into their silk fibers. The abundance of (13)C incorporated from the environment was determined by mass spectrometry and (13)C NMR measurements. Atmospheric CO(2) was incorporated into the silk fibers in the carbonyl groups of alanine, aspartic acid, serine, and glycine and the C(gamma) of aspartic acid. We show a simple model for the uptake of atmospheric CO(2) by silkworms. These results will demonstrate that silkworm has incorporated atmospheric CO(2) into silk fiber via the TCA cycle; however, the magnitude of uptake into the silk fibers is smaller than that consumed by the photosynthesis in trees and coral reefs.

It has been reported that carbonic anhydrase (CA) activity in plant leaves is decreased by Zn deficiency. We examined the effects of Zn deficiency on the activity of CA and on photosynthesis by leaves in rice plants (Oryza sativaL.). Zn deficiency increased the transfer resistance from the stomatal cavity to the site of CO2 fixation 2.3-fold and, consequently, the value of the transfer resistance relative to the total resistance in the CO2-assimilation process increased from 10% to 21%. This change led to a reduced CO2concentration at the site of CO2 fixation, resulting in an increased gradient of CO2 between the stomatal cavity and this site. The present findings support the hypothesis that CA functions to facilitate the supply of CO2 from the stomatal cavity to the site of CO2 fixation. We also showed that the level of mRNA for CA decreased to 13% of the control level during Zn deficiency. This decrease resembled the decrease in CA activity, suggesting the possible involvement of the CA mRNA level in the regulation of CA activity.

The relationship between leaf anatomy, ultrastructure and carbon discrimination was investigated in leaves of two F1hybrids (F1−1 and F1−2) between two different types of the grassPanicum[an NAD-malic enzyme (ME) C4species], which differ in bundle sheath ultrastructure. The female parent was Kabulabula grass, which has centrifugal chloroplasts in bundle sheath cells and is designated an NAD-ME(F) species, while the male parent was Makarikari grass, which has centripetal chloroplasts in the bundle sheath cells and is designated an NAD-ME(P) species. Suberin lamellae are present in Kabulabula grass but are lacking in Makarikari grass. Both F1hybrids had the same chromosome number (2n=36) as the parents but exhibited both univalent (about 45%) and bivalent (about 55%) chromosome pairing which was the major basis for the identification of F1hybrids. In F1−1, elongated bundle sheath cell chloroplasts are arranged mainly in a centripetal position, similar to those in the male parent, Makarikari grass. In contrast, most of the bundle sheath cells in F1−2 are packed with starch-containing chloroplasts, although in some cells chloroplasts tended to be centripetally arranged. In both F1hybrids, suberin lamellae were found in the bundle sheath cell walls, similar to the female parent, Kabulabula grass. The δ13C values of both F1hybrids were −11.4 to −11.7‰, almost the same as those of Kabulabula grass (−11.4‰), but significantly higher than those of Makarikari grass (−12.7‰). These results indicate that the chloroplast orientation in the bundle sheath cells and the presence of suberin lamellae are not obligatorily linked in their expression and suggest that suberin lamellae may play an important role in discrimination against13C.

Our previous paper showed that cultivar difference of flag leaf photosynthesis (LPS) in rice (Oryza sativa L.) was attributed to the difference in mesophyll resistance (rm). In this paper, we tried to divide rm into CO2 transfer resistance (rr) and CO2 fixation resistance (rc) for further analysis of rm by means of 3C determination of photosyntheti c products. In the heading time, rr, and rc occupied 14, and 58% in the total resistance, respectively, in average through 31 cultivars. This suggests that cultivar difference of LPS is mainly caused by the difference of r c. The percentage ratios of each resistance to the total one were maintained comparatively constant through the senescing process of the flag leaves. Moreover, the CO2 concentration in CO 2 fixating site showed almost the same values in different cultivars in a whole life span of a flag leaf. The rc showed a close correlation with ribulose-l,5-bisphosphate carboxylase/oxygenase (RubisCO) content. Carbonic anhydrase (CA) activity showed no correlation with rr, but showed positive correlation with rc. It was suggested that a mutual regulation system between CA activity and RubisCO activity could exist.

Tropospheric ozone is an air pollutant harmful to plants and animals. Its rapid increase at the ground surface has raised serious concern over damage to the quality and yield of agricultural crops. Reactive oxygen species (ROS) are formed in plant cells when that are exposed to a high concentration of ozone, and the ROS are thought to alter gene expression and result in cellular death. Clarification of the ROS formation will provide us with a better understanding of the physiological responses to and signaling pathways of ozone stress in plants. In this study, we investigated the mechanisms of the ROS formation in rice (Oryza sativa L.), the premier crop in Asia. To determine ROS distribution in rice leaves under acute ozone stress, we analyzed superoxide dismutase (SOD) expression, lipid peroxidation, NADPH oxidase activity, and in vivo H2O2 formation. Interestingly, chloroplastic, peroxisomal and mitochondrial SODs down-regulated their expression levels under ozone stress, whereas cytosolic SODs maintained their expression level. Higher lipid peroxidation occurred after the end of ozone exposure, which suggests lipid peroxidation may not be due to ozone directly, but rather to metabolic changes caused by the ozone exposure. Activity of NADPH oxidase did not show significant change. The in vivo analysis indicated accelerated formation of H2O2 about 24 h after the onset of exposure, which suggests that cellular death occurred around this time.

Reduction of relative growth rate (RGR) due to the NaCl treatment was examined in the seedlings of six Korean rice cultivars which had been reported to be different in salt tolerance on the level of grain yield. On the level of RGR, three of the cultivars were identified as salt tolerant, and the remaining three were identified as the sensitive cultivars. Further analysis of RGR indicated that the reduction of RGR by NaCl treatment was attributed in large part to the reduction of the net assimilation rate (NAR) rather than to that of the leaf area ratio (LAR). Leaf photosynthesis which is closely related with NAR, was also reduced by NaCl treatment in salt sensitive cultivars to a greater extent than tolerant cultivars. Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) content was determined in a tolerant cultivar, Han-Kang-Chal, and a sensitive one, Dong-Hae. Han-Kang-Chal showed a smaller decrease of Rubisco content per absorbed Na in the NaCl-treated leaves. This indicates that degradation of Rubisco by absorbed Na is slower in tolerant cultivars than in sensitive cultivars. Moreover, Han-Kang-Chal showed a larger decrease in osmotic potential in the NaCl treated leaves, suggesting that osmotic adjustment was developed under salt stress conditions in a tolerant cultivar.

Four enzymes, namely, the maize C(4)-specific phosphoenolpyruvate carboxylase (PEPC), the maize C(4)-specific pyruvate, orthophosphate dikinase (PPDK), the sorghum NADP-malate dehydrogenase (MDH), and the rice C(3)-specific NADP-malic enzyme (ME), were overproduced in the mesophyll cells of rice plants independently or in combination. Overproduction individually of PPDK, MDH or ME did not affect the rate of photosynthetic CO(2) assimilation, while in the case of PEPC it was slightly reduced. The reduction in CO(2) assimilation in PEPC overproduction lines remained unaffected by overproduction of PPDK, ME or a combination of both, however it was significantly restored by the combined overproduction of PPDK, ME, and MDH to reach levels comparable to or slightly higher than that of non-transgenic rice. The extent of the restoration of CO(2) assimilation, however, was more marked at higher CO(2) concentrations, an indication that overproduction of the four enzymes in combination did not act to concentrate CO(2) inside the chloroplast. Transgenic rice plants overproducing the four enzymes showed slight stunting. Comparison of transformants overproducing different combinations of enzymes indicated that overproduction of PEPC together with ME was responsible for stunting, and that overproduction of MDH had some mitigating effects. Possible mechanisms underlying these phenotypic effects, as well as possibilities and limitations of introducing the C(4)-like photosynthetic pathway into C(3) plants, are discussed.

An increase in atmospheric CO(2) concentration ( [CO(2)]) is generally expected to enhance photosynthesis and biomass. Rice plants (Oryza sativa L.) were grown in ambient CO(2) (AMB) or free-air CO(2)-enrichment (FACE), in which the target [CO(2)] was 200 micromol mol(-1) above AMB. (13)CO(2) was fed to the plants at different stages so we could examine the partitioning of photosynthates. Furthermore, canopy photosynthesis and respiration were measured at those stages. The ratio of (13)C content in the whole plant to the amount of fixed (13)C under FACE was similar to that under AMB at the vegetative stage. However, the ratio under FACE was greater than the ratio under AMB at the grain-filling stage. At the vegetative stage, plants grown under FACE had a larger biomass than those grown under AMB owing to enhancement of canopy photosynthesis by the increased [CO(2)]. On the other hand, at the grain-filling stage, CO(2) enrichment promoted the partitioning of photosynthate to ears, and plants grown under FACE had a greater weight of ears. However, enhancement of ear weight by CO(2) enrichment was not as great as that of biomass at the vegetative stage. Plants grown under FACE did not necessarily show higher canopy photosynthetic rates at the grain-filling stage. Therefore, we concluded that the ear weight did not increase as much as biomass at the vegetative stage owing to a loss of the advantage in CO(2) gain during the grain-filling period.

We have identified five recessive allelic mutations, mori1-1 to mori1-5, which drastically modify the shoot architecture of rice. The most remarkable feature of mori1 plants is a rapid production of small leaves and short branches. The mori1 plants are about 5 cm in height even 7 months after sowing. No reproductive growth was attained in mori1 plants even if inductive short-day treatment was applied. Leaves of mori1 at any position were very small and the size and shape were comparable to those of the wild-type 2nd leaf. The stem of mori1 7 months after sowing did not differentiate node and internode and had randomly oriented vascular bundles, which were characteristic of the basal part of the wild-type stem where 2nd and 3rd leaves were inserted. These structural characteristics indicate that mori1 maintains the 2nd-leaf stage (juvenile phase) of the wild type. The short plastochron and high cell division activity in the shoot apical meristem further confirmed the juvenility of mori1, corresponding to the 2nd-leaf-differentiation stage in the wild-type embryo. Furthermore, the apparent photosynthetic rate in mori1 leaves was low as in the wild-type 2nd leaf. Thus, mori1 is a heterochronic mutation that suppresses the induction of adult phase and the termination of the juvenile phase. Therefore, MORI1 plays an important role in the juvenile-adult phase change. The importance of heterochronic mutations in modifying shoot architecture is discussed.

Carbonic anhydrase (CA; EC.4.2.1.1) catalyzes the reversible conversion of CO2 to HCO3. CA has been recognized as an important enzyme that is closely associated with photosynthesis and the activity of CA can be specifically inhibited by zinc deficiency. In a previous study, we succeeded in estimating the magnitude of the CO2 transfer resistance (rr) from the intercellular space of mesophyll cells to the site of CO2 fixation in the chloroplasts (1). The purpose of the present study was to elucidate the relationship between the activity of CA and each component of mesophyll resistance and the mechanism of the specific inhibition of CA activity by using zinc deficient rice plants.

A new method of the construction of the colloidal dam in the aquifer utilizing the chamical reaction of Fe ion was investigated experimentaly, with the following results. (1) The clogging of the Fe (OH)3 in the one-dimensional experiments decreased the permeability, when the water, enriched with Fe ion, flowed for a long time. But the clogging is crushed and swept out when the inverse pressure gradient of more than 1.0×104 [Pa/m] was added. (2) The apparent thermal diffusivity decreased together with the permeability of the aquifer in the experiments with the two-dimensional model. It shows that the regional flow of the ground water gets out of the way from the colloidal domain constructed in the aquifer. (3) The field experiments showed that Fe ion was stored in the aquifer, decreasing the apparent thermal diffusivity by the yearly cycles. After the infection and recovery teatment the colloidal dam grows in the shape of a doughnut in the region where the pressure-gradient is less than 1.0×104 [Pa/m] in the aquifer.

For the thermal energy storage utilizing an aquifer, the selection of a suitable site is the most important process. The investigation to determine the proper process for site selection has been continued, based on previous field experiments and analyses. The results are as follows. (1) A process for the selection of a site suitable for aquifer thermal energy storage has been proposed. (2) A new method for determining the most suitable site in terms of values of the apparent thermal diffusivity of the aquifer has been proposed. This model is based on the analytical results of temperature recovery in the well after stepwise injection of warm water in the aquifer. (3) The experimental results obtained showed good agreement with those of the proposed method.