Saturated hydraulic conductivity of compacted bentonite-sand mixtures before and after gas migration in artificial seawater

To understand the self-healing property of an engineered barrier for radioactive waste disposal,the hydraulic conductivity of compacted bentoniteesand mixtures saturated with artificial seawater(SW)before and after gas migration was examined.Na-and Ca-bentonites were mixed with fine sand at a ratio of 70%bentonite in dry weight.Two aspects were considered during the experiment:the hydraulic conductivity of the specimen that was resaturated after gas migration and the distribution of water content immediately after gas migration to study gas migration pathways.The gas migrated through the entire cross-section of the specimen,and gas breakthrough occurred in the equilibrium swelling pressure range approximately.Subsequently,the gas flow rate reached a sufficient large value when the gas pressure was approximately twice the equilibrium axial pressure(the sum of swelling and confining pressures),which excluded the back pressure.Although the gas migration pathway was not visible when the specimen was observed immediately after gas migration,the water content distribution showed that several parts of the specimen with lower water content were connected in the direction of gas migration.After resaturation,the change in permeability was within a limited rangedtwo to three times larger than that before gas migration for each type of bentonite in SW.This slight change suggests that gas migration creates a pore structure that cannot be sealed via crystalline swelling of montmorillonite in SW,even if highly compacted bentonite is used under a constant-volume condition.

A new model for evaluating the dynamic shear strength of rocks based on laboratory test data for earthquake-resistant design

The dynamic shear strength of rocks is required for the earthquake-resistant design of nuclear power plants in Japan.This research aims to propose a mathematical model for estimating the dynamic strength and to validate the model.Two different types of specimens were prepared for the model validation,and the monotonic and cyclic loading tests were conducted to obtain the mathematical model parameters.Subsequently,multistep cyclic loading tests were performed,followed by simulations using the mathematical model.The test results demonstrated that the dynamic shear strength exceeded the static shear strength,which agreed with previous researches.Furthermore,the dynamic shear strength calculated using the mathematical model was generally consistent with that obtained from the experimental data.

Projections of ocean climate for northwestern Pacific Ocean

The long-term adjustment processes of atmosphere and ocean in response to gradually increased atmospheric CO2 concentration have been analyzed in 70 and 140 a integrations with NCAR fully-coupled climate system model (CSM). In these experiments the CO2 concentration has been increased to double and quadruples the initial concentration, respectively. After 70 a, at the time of CO2 doubling, the model predicts surface air temperature rises by 1.2 and 1.5 K for the globe and the northwestern Pacific Ocean, respectively. The behavior of the quadrupling run is similar: each global and regional mean surface air temperatures increase by 2.8 and 3.0 K at the time of CO2 quadrupling. From the experiments, surface air temperature changes in the northwestern Pacific Ocean will be more distinctive compared with the global average, mainly due to exceptionally large wanning and sea level change near the entrance of the Kuroshio extension.

Large deformation simulations of geomaterials using moving particle semi-implicit method

Numerical simulation tools are required to describe large deformations of geomaterials for evaluating the risk of geo-disasters. This study focused on moving particle semi-implicit(MPS) method, which is a Lagrangian gridless particle method, and investigated its performance and stability to simulate large deformation of geomaterials. A calculation method was developed using geomaterials modeled as Bingham fluids to improve the original MPS method and enhance its stability. Two numerical tests showed that results from the improved MPS method was in good agreement with the theoretical value.Furthermore, numerical simulations were calibrated by laboratory experiments. It showed that the simulation results matched well with the experimentally observed free-surface configurations for flowing sand. In addition, the model could generally predict the time-history of the impact force. The MPS method could be a useful tool to evaluate large deformation of geomaterials.

Improvement on Quantitative Measurement of Fly Ash Contents Using Laser-Induced Breakdown Spectroscopy

Contents of fly ash are important factors for the operation of coal-fired plants. Real-time monitoring of coal and fly ash such as unburned carbon in fly ash can be an indicator of the combustion conditions. Because of the strong signal intensity and the relative simplicity of the LIBS (Laser- Induced Breakdown Spectroscopy) technique, LIBS can be applicable for real-time composition measurement of coal and fly ash. This research presented here focused on the clarification of the effects of plasma temperature and coexisting materials on quantitative measurement of fly ash contents. Quantitative capability of LIBS was improved using the proposed plasma temperature correction method. The CO2 effect was also discussed to accurately evaluate unburned carbon in fly ash in exhausts. Using the results shown in this study, quantitative measurement of fly ash contents has been improved for wider applications of LIBS to practical fields.

Use of Real- time RT-PCR Analysis for mRNA Expression of Tobacco Ferritin Gene (NtFer1)

To understand the use of real-time reverse transcription-polymerase chain reaction （real-time RT-PCR） for detecting the relative abundance of mRNA, the expression of a tobacco ferrltin gene （NtFer1） was detected by Northern blot and real-time RT-PCR. The results indicated that both of the two methods were able to detect mRNA expression of NtFer1 cleady and similady, namely NtFer1 expression was responsive to iron-ovedoad, and the abundance of NtFer1 mRNA was greatly increased after iron loaded for 6 h. To compare the effect and sensitivity of two methods, results revealed that Northern blot need 30 μg of total RNA and at least 3 days for the total protocol performance, whereas real-time RT-PCR only need 2 μg of total RNA and 1.5 h. The real-time RT-PCR is rather sensitive and effective than Northern blot. Real-time RT-PCR analysis can be used to rapidly detect the relative abundance of mRNA expression instead of Northern blot analysis.

Stick–slip behavior of Indian gabbro as studied using a NIED large-scale biaxial friction apparatus

This paper reports stick-slip behaviors of Indian gabbro as studied using a new large-scale biaxial friction apparatus, built in the National Research Institute for Earth Science and Disaster Prevention （NIED）, Tsukuba, Japan. The apparatus consists of the existing shaking table as the shear-loading device up to 3,600 kN, the main frame for holding two large rectangular prismatic specimens with a sliding area of 0.75 m^2 and for applying normal stresses an up to 1.33 MPa, and a reaction force unit holding the stationary specimen to the ground. The shaking table can produce loading rates v up to 1.0 m/s, accelerations up to 9.4 m/s^2, and displacements d up to 0.44 m, using four servocontrolled actuators. We report results from eight preliminary experiments conducted with room humidity on the same gabbro specimens at v = 0.1-100 mm/s and an = 0.66-1.33 MPa, and with d of about 0.39 m. The peak and steady-state friction coefficients were about 0.8 and 0.6, respectively, consistent with the Byerlee friction. The axial force drop or shear stress drop during an abrupt slip is linearly proportional to the amount of displacement, and the slope of this rela- tionship determines the stiffness of the apparatus as 1.15 × 10^8 N/m or 153 MPa/m for the specimens we used. This low stiffness makes fault motion very unstable and the overshooting of shear stress to a negative value was recognized in some violent stick-slip events. An abrupt slip occurred in a constant rise time of 16-18 ms despite wide variation of the stress drop, and an average velocity during an abrupt slip is linearly proportional to the stress drop. The use of a large-scale shaking table has a great potential in increasing the slip rate and total displacement in biaxial friction experiments with large specimens.

Progress in Physics and Technology Developments for the Modification of JT-60

Recent progress in the physics and engineering design study for themodification programme of JT-60 is presented. In order to achieve a steady state high-βplasmaoperation, which is the dominant issue of this programme, physics design for the MHD control and thestability analysis is investigated. Engineering design and the R & D for the superconducting coils,irradiation shield are performed well towards the mission of programme.

Possible Effect of Pressure Solution on the Movement of a Canister in the Buffer of Geological Disposal System

One of the major concepts of the geological disposal of high level radioactive waste is to enclose a metallic container with bentonite buffer which is considered to be impermeable and chemically stable. Since the average density of the container is around 6 to 7 and very heavy compared to bentonite, the scenario of container sinking has been evaluated because excess sinking makes short the pathway of nuclide migration in the bentonite and is detrimental to the safety of the disposal system. Previous considerations on container sinking have been made from the viewpoint of mechanical deformation of the bentonite. In this paper, a chemical deformation process is presented as another mechanism of container sinking, which has not been previously considered for the container sinking in the field of radioactive waste disposal. The chemical deformation mentioned in this paper is the deformation through the process of pressure solution of minerals constituting the buffer, transportation by diffusion and precipitation. That such chemical deformation is a ubiquitous phenomenon occurring in various scales in the crust of the earth will be shown through the review of previous works. Then, some future research topics will be suggested which would be required in order to evaluate the container sinking in the safety case for radioactive waste disposal.

Pitfalls and Remedies in DEA Applications: How to Handle an Occurrence of Zero in Multipliers by Strong Complementary Slackness Conditions

This study discusses a guideline on a proper use of Data Envelopment Analysis (DEA) that has been widely used for performance analysis in public and private sectors. The use of DEA is equipped with Strong Complementary Slackness Conditions (SCSCs) in this study, but an application of DEA/SCSCs depends upon its careful use, as summarized in the guideline. The guideline consists of the five suggestions. First, a data set used in the DEA applications should not have a ratio variable (e.g., financial ratios) in an input(s) and/or an output(s). Second, radial DEA models under variable and constant Returns to Scale (RTS) need a special treatment on zero in a data set. Third, the DEA evaluation needs to drop an outlier. Fourth, an imprecise number (e.g., 1/3) may suffer from a round-off error because DEA needs to specify it in a precise expression to operate a computer code. Finally, when a large input or output variable may dominate other variables in DEA computation, it is necessary to normalize the data set or simply to divide each observation by its average. Such a simple treatment produces more reliable DEA results than the one without any data adjustment. This study also discusses how to handle an occurrence of zero in DEA multipliers by applying SCSCs. The DEA/SCSCs can serve for a multiplier restriction approach without any prior information. Thus, the propesed DEA/SCSCs can provide more reliable results than a straight use of DEA.

Analysis of Pb-Bi Vessel Wall Ablation Experiment with High Temperature Liquid by MPS Method

In a severe accident of a light water reactor, ablation of the RPV （reactor pressure vessel） lower head by corium is a key phenomenon, which affects progression of the accident. The MPS （moving particle semi-implicit） method is one of particle methods that calculate behavior of incompressible fluid by semi-implicit method. In preceding studies, the MPS method has been extensively studied and developed for simulations of different phenomena involved in severe accident of nuclear reactors. This paper aims to investigate whether the MPS method is capable of analyzing the lower head ablation phenomenon. The small-scale experiment carried out at CRIEPI （Central Research Institute of Electric Power Industry） using Pb-Bi vessel and silicone oil was analyzed for the validation of the MPS method. The MPS analysis well reproduced the experimental phenomena qualitatively. However, with respect to some quantitative results, more investigation such as influence of the calculation particle size is necessary.

碳化镍钼催化剂的制备及其甲烷干气重整活性(英文)

Nickel molybdenum carbide catalysts were prepared and their activities in the CO2 reforming of methane at a low CO2/CH4 reactant ratio were investigated using a microreactor at atmospheric pressure and at 973 K.The effect of the catalyst preparation method and the Ni/Mo ratio on the increase in catalyst life and the promotion of catalytic activity were investigated using N2 adsorption,X-ray diffraction, temperature-programmed carburization,temperature-programmed reaction,and a reforming reaction.The 25Ni75Mo catalyst that was carburized at 813 K exhibited the highest hydrogen formation ability and gave the least carbon deposition.The incomplete carburization of the Mo oxide species in the catalyst that was carburized at a lower temperature gradually gave a more active carburized species.The NiMoOxCy in the catalyst was more active in hydrogen formation during the dry reforming of methane whileβ-Mo2C andη-Mo3C2 were less active.

国际合作情况下的锂电池的寿命测试程序(英文)

为了满足不同的技术和经济目标,从轻度混合动力、插电式混合动力到全电池动力的电动汽车,都将依赖于新型的、先进的(如基于锂的)蓄电池。这些电池在各种应用条件下的性能预测和寿命表征费工、费时,目前尚未得到充分的发展。一些国家已投入资金和人力进行相关的研究,其实通过国际合作,这些努力和花费也许能发挥更大的作用,例如目前正在国际能源机构(The International Energy Agency,IEA)框架内开展的准备工作。正在致力于开发一套标准化的、加速的测试程序,将允许各个测试机构合作分析电池的测量数据。该文评述了欧洲、日本和美国在加速寿命测试程序上的最新进展。以国际合作为目标,搜集、对比和分析现有的测试程序。

Analysis on EAST LHCD Operation Space by Using Simple Core-SOL-Divertor Model

A simple core-SOL-divertor model （CSD model） was developed to investigate qual- itatively the overall features of the operational space for the integrated core and edge plasma. In the CSD model, the core plasma model of ITER physics guidelines and the two-point SOL-divertor model are applied, This CSD model is validated by the two dimensional divertor transport code （B2-EIRINE） and by the JT-60U divertor recycling database, and this model is applicable to the low- and high-recycling state of the divertor plasma. The CSD model is applied to the study of the EAST operational space with lower hybrid current drive under various kinds of trade-off for the basic plasma parameters, and the relationship between the operational space and the plasma discharge duration is also discussed.

Predictions for EAST Divertor Performance

A detailed study of the divertor performance in EAST has been performed for both its double null （DN） and single null （SN） configurations. The results of application of the SOLPS （B2-Eirene） code package to the analysis of the EAST divertor are summarized. In this work, we concentrate on the effects of increased geometrical closure and of magnetic topology variation on the scrape-off layer （SOL） and divertor plasma behavior. The results of numerical predictions for the EAST divertor operational window are also described in this paper. A simple Core-SOL- Divertor （C-S-D） model was applied to investigate the possibility of extending plasma operational space of low hybrid current drive （LHCD） experiments for EAST.

A numerical study of summer ozone concentration over the Kanto area of Japan using the MM5/CMAQ model

We assessed the ability of the MM5/CMAQ model to predict ozone （O3） air quality over the Kanto area and to investigate the factors that affect simulation of O3. We find that the coupled MM5/CMAQ model is a useful tool for the analysis of urban environmental problems. The simulation results were compared with observational data and were found to accurately replicate most of the important observed characteristics, The initial and boundary conditions were found to have a significant effect on simulated O3 concentrations. The results show that on hot and dry days with high O3 concentration, the CMAQ model provides a poor simulation of O3 maxima when using initial and boundary conditions derived from the CMAQ default data. The simulation of peak O3 concentrations is improved with the JCAP initial and boundary conditions. On mild days, the default CMAQ initial and boundary conditions provide a more realistic simulation. Meteorological conditions also have a strong impact on the simulated distribution and accumulation of O3 concentrations in this area. Low O3 concentrations are simulated during mild weather conditions, and high concentrations are predicted during hot and dry weather. By investigating the effects of different meteorological conditions on each model process, we find that advection and diffusion differ the most between the two meteorological regimes. Thus, differences in the winds that govern the transport of O3 and its precursors are likely the most important meteorological drivers of ozone concentration over the central Kanto area.

Inelastic constitutive equation of plasma-sprayed ceramic thermal barrier coatings

Ceramic thermal barrier coatings （TBCs） are a very important technology for protecting the hot parts of gas turbines （GTs） from a high-temperature environment. The coating stress generated in the operation of GTs brings cracking and peeling damage to the TBCs. Thus, it is necessary to evaluate precisely such coating stress in a TBC system. We have obtained a stress-strain curve for a freestanding ceramic coat specimen peeled from a TBC coated substrate by conducting the bending test. The test results have revealed that the ceramic coating deforms nonlinearly with the applied loading. In this study, an inelastic constitutive equation for the ceramic thermal barrier coatings deposited by APS is developed. The obtained results are as follows： （1） the micromechanics-based constitutive equation was formulated with micro crack density formed at splat boundary, and （2） it was shown that the numerical results for a nonlinearly deformed beam simulated by the developed constitutive equation agreed with the experimental results obtained by cantilever bending tests.

Simulation of long-term nutrient removal in a full-scale closed-loop bioreactor for sewage treatment： an example of Bayesian inference

In this study, the performance of nitrogen and phosphorus removal in a full-scale closed-loop bioreactor （oxidation ditch） system was simulated using the ASM2d model. Routine data describing the process for two years were compiled for calibration and validation. To overcome the identifiability problem, the classic Bayesian inference approach was utilized for parameter estimation. The calibrated model could describe the long-term trend of nutrient removal and short-term variations of the process performance, showing that the Bayesian method was a reliable and useful tool for the parameter estimation of the activated sludge models. The anoxic phosphate uptake by polyphosphate accumulating organisms （PAO） contributed 71.2% of the total Poly-P storage, which reveals the dominance of denitrifying phosphorus removal process under the oxygen limiting conditions. It was found that 58.7% of the anoxic Poly-P storage and denitrification by PAO in the reactor was achieved in the aerated compartment, implying that the PAO＇s anoxic activity was significantly stimulated by the low dissolved oxygen （DO） level in this compartment due to the oxygen gradient caused by brush aerator.

NAD＋ Accumulation during Pollen Maturation in Arabidopsis Regulating Onset of Germination

Although the nicotinamide nucleotides NAD（H） and NADP（H） are essential for various metabolic reactions that play major roles in maintenance of cellular homeostasis, the significance of NAD biosynthesis is not well under- stood. Here, we investigated the dynamics of pollen nicotinamide nucleotides in response to imbibition, a representative germination cue. Metabolic analysis with capillary electrophoresis electrospray ionization mass spectrometry revealed that excess amount of NAD＊ is accumulated in freshly harvested dry pollen, whereas it dramatically decreased immedi- ately after contact with water, importantly, excess of NAD~ impaired pollen tube growth. Moreover, NAD~ accumulation was retained after pollen was imbibed in the presence of NAD^-consuming reaction inhibitors and pollen germination was greatly retarded. Pollen deficient in the nicotinate/nicotinamide mononucleotide adenyltransferase （NMNAT） gene, encoding a key enzyme in NAD biosynthesis, and a lack of NAD＊ accumulation in the gametophyte, showed precocious pollen tube germination inside the anther Iocule and vigorous tube growth under high-humidity conditions. Hence, the accumulation of excess NAD＊ is not essential for pollen germination, but instead participates in regulating the timing of germination onset. These results indicate that NAD＋ accumulation acts to negatively regulate germination and a decrease in NAD＋ plays an important role in metabolic state transition.