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The failure mode of concrete columns in subway stations during seismic events can be affected by the dynamic fluctuation of the axial forces. This study conducted quasi-static tests with bidirectional loading on three scaled rectangular columns to investigate the influence of highly variable axial compression ratio (ACR). A detailed analysis was conducted of the impact of the highly variable ACR on the column failure mode, reinforcement strains, and hysteretic behavior, and the repairability assessment was discussed. Numerical analysis of the effect of ACR variations was carried out based on the experimental results. In these experiments, the failure modes of central columns in Dakai Station, Japan, during the Kobe earthquake were reproduced, and three columns exhibited compressive-bending-shear damage and compressive-bending damage. As the ACR varied up to three cycles during one horizontal loading cycle, the hysteresis curve of the columns exhibited notable asymmetry. Furthermore, with a large variation of ACR amplitude, the stirrups of the column were fractured due to excessive shear effects. The bearing capacity, energy dissipation, and stiffness degradation of the columns were significantly adversely affected. A reparability assessment of the columns, based on the distribution of reinforcement strains, residual displacements, and concrete damage, is proposed. The effects of varying frequency and amplitude of different vertical ACRs on the hysteretic behavior of columns were analyzed numerically. [ABSTRACT FROM AUTHOR]

Resource harvesting in inland fisheries during a single fishing season is mathematically modeled based on an extended mean field game played by many anglers. The harvesting rate of each angler depends on that of the others through a mean field interaction. Each angler wants to maximize fishing utility, while resource overexploitation is effectively penalized through incentives for conservation. Anglers' fishing activities are represented by controlled jump processes arising as a unique nonlinearity in the extended mean field game. Solving the extended mean field game reduces to the resolution of a forward-backward system containing a Hamilton–Jacobi–Bellman and Fokker–Planck equations coupled through the controlled harvesting rate. The average total visiting time per angler during the fishing season is obtained as a byproduct from the forward-backward system, which is used to investigate the scheme of license fee of inland fisheries. A finite difference method is proposed to numerically compute the forward-backward system based on a Picard iteration. The convergence of the numerical solution to the Hamilton–Jacobi–Bellman equation is analyzed through discontinuous viscosity solutions. Finally, we specify fish population dynamics based on the unique data of the major inland fishery resource Plecoglossus altivelis altivelis during 2023 in Japan. Computational examples are presented to analyze our mathematical model. • We formulate a novel extended mean field game of inland fisheries. • Mutually-coupled Hamilton–Jacobi–Bellman and Fokker–Planck equations are obtained. • Their finite difference discretization leads to a system of limit equations. • Solutions to the limit equations are discussed through discontinuous viscosity solutions. • We present a demonstrative application example to Plecoglossus altivelis during 2023 in Japan. [ABSTRACT FROM AUTHOR]

In Japan, small agricultural tractors without axle suspensions used on bumpy farm roads experience severe vibrations. Excessive vibrations often cause tyres to lose contact with the supporting ground or decrease the vertical tyre force such that the cornering force exceeds the static friction limit. The resulting bouncing and sliding motions induce steering instability, resulting in overturning accidents. This study investigated the effectiveness of axle suspension in alleviating bump disturbance-induced steering instability in small tractors. A step lane change test involving bump disturbances was newly proposed for the steering stability testing of small tractors. The numerical experiments compared four axle suspension structures: no-, front-, rear-, and full-suspensions. The results showed that bump disturbances induce steering instability in the no- and rear-suspension tractors. In contrast, the front- and full-suspension structures significantly improved the steering stability of the tractor by keeping the steering wheel in contact with the ground. The proposed testing method helped evaluate improvements in the steering stability brought about by increasing the ground contact of the steering wheel. Our results can aid in designing and testing suspension systems for small tractors. • Tractor bouncing, sliding, and driver models were newly coupled for simulations. • Step lane change involving bump disturbances was proposed for stability test. • Steering instability was found in the no- and rear-suspension tractors. • Front- and full-suspensions could significantly alleviate steering instability. [ABSTRACT FROM AUTHOR]

The south-eastern offshore of the Boso Peninsula in Japan periodically experiences short-term slow slip events (SSEs) every few years. On 2018 June, an SSE occurred with the maximum surface horizontal displacement reaching up to 4.7 cm by according to the operational global navigation satellite system (GNSS) network. This study performed a time-series analysis of interferometric synthetic aperture radar (InSAR) with Sentinel-1 SAR images to investigate detailed spatial pattern of surface displacements caused by the SSE. With the assistance of an atmospheric delay correction with a regional numerical weather model output, the InSAR time-series analysis successfully captured displacement signals in three paths, whose maximum amplitudes in line-of-sight directions were 1.46, 1.86 and −0.80 cm. A checkerboard test revealed that the resolution of the slip inversion was higher when InSAR was used than that using GNSS, especially in and around the inland. The slip inversion with the actual displacement data derived from the InSAR time-series analysis was performed with the L-curve optimization, showing that the estimated slip area was concentrated offshore south-eastward from the Boso Peninsula with the maximum slip of 5 cm and the estimated moment magnitude of 6.4. As similar to previous SSEs in the Boso Peninsula, a seismic swarm simultaneously occurred in the downdip area adjacent to the estimated slip with the SSE occurrence, suggesting a different friction characteristics between them. This study demonstrates usefulnesses of the InSAR observation for capturing detailed spatial characteristics of small-displacement events like SSEs and of the hybrid use of the externally derived delay correction with the time-series analysis to improve the displacement detection accuracy. [ABSTRACT FROM AUTHOR]

Background: Benralizumab is an anti‐interleukin‐5 receptor α monoclonal antibody approved as an add‐on maintenance treatment for patients with uncontrolled severe asthma. Prior Phase 3 studies have evaluated benralizumab in patients aged ≥12 years with severe uncontrolled asthma. The TATE study evaluated the pharmacokinetics (PK), pharmacodynamics (PD), and safety of benralizumab treatment in children. Methods: TATE was an open‐label, Phase 3 study of benralizumab in children aged 6–11 years from the United States and Japan (plus participants aged 12–14 years from Japan) with severe eosinophilic asthma. Participants received benralizumab 10/30 mg according to weight (<35/≥35 kg). Primary endpoints included maximum serum concentration (Cmax), clearance, half‐life (t1/2), and blood eosinophil count. Clearance and t1/2 were derived from a population PK (popPK) analysis. Safety and tolerability were also assessed. Results: Twenty‐eight children aged 6–11 years were included, with an additional two participants from Japan aged 12–14 years also included in the popPK analysis. Mean Cmax was 1901.2 and 3118.7 ng/mL in the 10 mg/<35 kg and 30 mg/≥35 kg groups, respectively. Clearance was 0.257, and mean t1/2 was 14.5 days. Near‐complete depletion of blood eosinophils was shown across dose/weight groups. Exploratory efficacy analyses found numerical improvements in mean FEV1, mean ACQ‐IA, patient/clinician global impression of change, and exacerbation rates. Adverse events occurred in 22/28 (78.6%) of participants; none led to discontinuation/death. Conclusion: PK, PD, and safety data support long‐term benralizumab in children with severe eosinophilic asthma, and were similar to findings in adolescents and adults. Trial Registration: ClinicalTrials.gov‐ID: NCT04305405. [ABSTRACT FROM AUTHOR]

Densely built areas with poor thermal insulation suffer from high thermal environmental risks and generally consume high energy in summer. Determining the relationship between density and energy consumption is necessary, particularly when implementing urban heat island (UHI) countermeasures. This study evaluated the effects of density and UHI countermeasures on the energy consumption and indoor thermal comfort of a detached house in a typical densely built wooden house area in Yokohama City, Japan. Three densities and six countermeasures were considered. Annual hourly simulations based on the SCIENCE-Vent thermal environment simulation model yielded the following results: in densely built wooden house areas, the energy consumption and thermal discomfort increased with density. The green roof yielded the largest energy savings in the cooling and heating seasons, demonstrating the highest annual energy savings with 5.7%. Density had little impact on rooftop countermeasures, but the effect of the high-reflectance walls increased with density, and the reduction in annual energy consumption (air conditioning and lighting) is 2.6%, 3.0%, 3.6% in 37%, 47%, and 59% density cases, respectively. The impact of thermal countermeasures on indoor thermal comfort varied according to the thermal control mechanism. [ABSTRACT FROM AUTHOR]

Accidental inhalation intake of plutonium isotopes and 241Am occurred at a Pu research facility in Japan in 2017, and the five workers involved in this accident were treated by the administration of Ca/Zn-diethylenetriaminepentaacetic acid (DTPA). For the worker who was most internally exposed, the therapy was continued over 1 y after the accident. Urinary samples collected before and after each administration were subject to bioassay to evaluate the efficacy of the dose reduction. This study performed numerical analyses using a biokinetic model dealing with 241Am-DTPA with reference to the European Coordinated Network on Radiation Dosimetry approach, which assumes that the complex of actinides and Ca/Zn-DTPA is generated in the designated compartments in the biokinetic model. The results of the model prediction well captured the trend of the observed urinary excretion in the long-term bioassay and would be useful to evaluate the efficacy of the Ca/Zn-DTPA administration for the worker involved in the accident. [ABSTRACT FROM AUTHOR]

Wireless power transfer to electric vehicles while driving is a technology that is currently attracting attention as it has the potential to solve the problems faced by EVs that will become popular worldwide in the future. In the case of dynamic wireless power transfer (DWPT) to electric vehicles, it is necessary to transmit the required power with high efficiency and ensure safety. While there are multiple safety requirements, there are also regulatory values for the magnetic field strength emitted from the coil, which must be satisfied before it can be implemented in society. This research aims to speed up the design of coils by using only numerical analysis, in contrast to conventional coil design using electromagnetic field analysis. In the future construction of wireless power transfer systems, it is of great significance to discuss the design using only numerical analysis, as there are many design parameters. Experiments were carried out and compared with the numerical analysis and found to be in agreement. A power transmission of 20 kW converted value was carried out to verify the effect of the size, pitch, and number of turns of the transmission coils on the efficiency and magnetic field strength. The effect of input voltage was also discussed by simulation, and the optimum coil was derived. As a result, when the coil size was 800 × 600 mm, the number of turns was 46, the pitch was 6.1 mm and the input voltage was 1400 V, the analysis showed that a power transmission of 20 kW with an efficiency of 99.3% and a far magnetic field leakage strength of 81.6 dBμA/m could be achieved. Even with a coreless coil, the magnetic field strength could be below the regulation value. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Natural ester is viewed as the most promising future alternative to mineral oil due to its high degradability, but its inferior breakdown characteristics prevent its application of large power equipment. The purpose of this research is to investigate the breakdown characteristics of natural ester. First, the natural ester's ionization potential and molecular number density are calculated. Then, an improved natural ester streamer discharge model is developed using the Poisson's equation and the carrier continuity equation, taking into account the effect of temperature on carrier mobility and incorporating the computed ionization potential and other factors. The results for different lightning impulse voltages were analyzed by COMSOL software. Comparing the mineral oil, the results indicate that the natural ester breakdown voltage is close to and slightly lower than that of the mineral oil but the acceleration voltage is very similar to the breakdown voltage. The lower ability of esters in prevention against the development of fast and energetic streamers is consistent with the description of the experimental results. In addition, the model takes into account the effect of temperature on the carrier mobility. As the applied voltage increases, the change of temperature in the streamer channel accelerates the carrier motion and promotes the propagation of the streamer. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Many old telecommunication pipes built during the 1960s and 1970s are still in use in Japan. Past earthquake surveys have found that old-standard rigid polyvinyl chloride (PVC) pipes with adhesive joints are vulnerable to earthquakes, and it appears that such pipes were damaged by fault displacement during the 2016 Kumamoto earthquake. However, the safety of old-standard rigid PVC pipes in the event of fault displacement has not been evaluated. The present study evaluated the safety of old-standard PVC pipes in the event of fault displacement in finite element analysis. First, an analysis model of a pipe with an adhesive joint was developed in the numerical analysis of a bending test. An analysis model of the soil-pipe interaction was then developed in a numerical analysis of a soil-tank test. It was confirmed that the results of the bending test and the soil-tank test were accurately reproduced using the developed model. After confirming that the analysis results agree well with experimental results, a numerical analysis of the safety evaluation in the event of fault displacement was conducted. The results showed that when the joint center was located 300 mm from the fault plane where the maximum principal stress occurs and when the fault plane is perpendicular to the pipes, the yielding occurred with the smallest fault displacement of 55 mm for the new pipe and only 25 mm for removed pipes. The analysis showed that even a small displacement may cause serious damage to the old-standard rigid PVC pipes with an adhesive joint. [ABSTRACT FROM AUTHOR]

The voltage across a 77‐kV‐class transmission line surge arrester (TLSA) and the heat in the TLSA have been computed using the finite‐difference time‐domain (FDTD) method for a lightning current having a magnitude of 50 kA, a risetime of 1 μs, and a half‐peak width of about 100 μs. The TLSA is represented with series‐connected‐nine ZnO elements, each of which has a length of 36 mm and a diameter of 32 mm. The ZnO element is represented with many 2 × 2 × 2 mm cubic cells, each of which has a nonlinear resistivity in each of the x‐, y‐, and z‐directions dependent on the electric field in each direction and the temperature in each cell. From the spatial and temporal distributions of FDTD‐computed heat in the TLSA, the spatial and temporal distributions of thermal stress in the TLSA have been computed using the finite‐element method. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) has been attracting a lot of attention in recent years for its ability to greatly improve the convenience of our lives. Moreover, WPT for Electric Vehicles (EVs) has become an important key to the spread of EVs. The efficiency of WPT using magnetic field resonant coupling can be evaluated by the kQ product, but the optimal coil design method to maximize the kQ product at a specific frequency has not yet been established. In this paper, taking the Test station GA‐WPT1 and the Test station VA‐WPT1/Z3 of SAE J2954, which is officially defined as the standard for WPT while the electric vehicle is stationary in October 2020, as examples, the coil parameters that maximize the kQ product in the case of the coreless are determined according to the proposed method. An efficiency of 99.13% was obtained with a transmission distance of 200 mm and the number of turns of N1 = 34 and N2 = 30. Also, since all analyses can be derived immediately except for the analysis of the Litz wire to be used, the optimization time could be reduced significantly compared with the electromagnetic field analysis. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Summary: The damped outrigger system is known to efficiently provide additional damping in buildings with heights of over 250 m. However, particularly for supertall buildings in the center of Tokyo, Japan, the outrigger truss from the center core to the exterior columns need to span distances of more than 20 m. This increases the flexural stiffness demand on the outrigger that leads to larger truss depths making the damped outrigger system inefficient. For such tall buildings with large plans, a new damping modification system, the "damped braced tube system" is proposed, where the exterior surface of the elastic mega braces are partially removed vertically to create a split and are replaced with dissipaters (energy‐dissipation devices). The damped braced tube system enhances the seismic performance as the exterior surfaces of the elastic mega braces work together with the damped slits like in a coupled wall system and increases the overall damping ratio. In this paper, numerical models were constructed based on a real project in Japan consisting of a 397‐m supertall building employing the damped tubular braced system using oil dampers (referred to as viscous dissipaters). A series of generalized response spectrum based numerical analyses and optimizations were performed to minimize the seismic response. The proposed system exhibited improved damping performance with the first to third mode damping ratios reaching to more than 7% while providing a wide range of options for dissipater distribution for design. Finally, the elevation of the slit's base is recommended to be equal to 0.22 of the total building height considering the trade‐off relationship between the first modal damping ratio and the fundamental period. [ABSTRACT FROM AUTHOR]

With the increasing of extreme rainfall frequency, landslides accompanied by mudslides often lead to serious casualties and property damage. On 3rd July 2021, a debris flow occurred in Izu Mountain area, Shizuoka County, Japan, and then resulted in 26 deaths and 131 houses destroyed, where houses were mainly built along the banks of the creek. In order to analyse the landslide state and distribution, a two-dimensional debris flow dynamic model (Massflow) was selected to simulate the process of the landslide-generated debris flow. When the model results are considered together with remote sensing images, the volume distribution of the unstable landslide is also able to be determined. The results show that (1) the affected areas are mainly concentrated at the outfall of the gully and on both sides of the streets. (2) The pore pressure ratio is an important factor affecting the damage range of this debris flow. (3) The increase of the pore pressure ratio in the landslide make the movement distance of debris flow increase significantly. [ABSTRACT FROM AUTHOR]

Around the world, and especially in Japan, the tearing down of social infrastructure, including civil engineering structures, has been increasing due to the aging of these constructions, which were built during a period of high economic growth, and a decrease in their utilization caused by a recent drop in the population. The number of existing pile foundations being pulled out has gradually risen to a higher number than that of pile foundations being newly installed. However, after the pulling-out of a pile foundation, the mechanical characteristics of the surrounding ground are of great concern due to the existence of the holes that form when the existing piles are removed (extraction holes). In this study, a three-dimensional elasto-plastic consolidation analysis was performed to examine the effect of the extraction holes of removed piles on the static properties of the surrounding ground. As examples of the results of the analysis, if an extraction hole of a removed pile is left as it is, large ground subsidence will occur near the extraction hole of removed pile, especially at the lower part of the clay layer near the hole. The greater the number of extraction holes of removed piles, the greater the compressive stress acting on the extraction holes after the pile removal. Therefore, the filler should exhibit strength early as the number of extraction holes of removed piles increases. [ABSTRACT FROM AUTHOR]

Paleotsunami studies along the Pacific coast of Tohoku, northern Japan, have been considerably developed recently, particularly after the massive impact of the 2011 Tohoku-oki tsunami. Nevertheless, in the southernmost Shimokita Peninsula, studies pertaining to paleotsunami are underdeveloped, leading to a vague understanding of the tsunamigenic sources northward of the Tohoku region, along with incomplete hazard evaluation. Paleotsunami deposits in Shimokita can be related not only to the Japan Trench along the Sanriku coast but also to the Kuril trench along the Pacific coast of Hokkaido. In this study, we unveiled the paleotsunami history of Hachinohe in northern Tohoku. Using a combination of sedimentological, geochemical, paleontological, and mineralogical proxies, we characterized seven sand layers that dated from ca. 2700 to ca. 5500 yr BP based on radiocarbon (14C) ages as event deposits of marine origin. Sedimentological and paleontological evidence coupled with ground-penetrating radar imagery revealed a marsh environment comprising successive extinct ponds, controlling the depositional environment. Numerical modeling ruled out the possibility of storms as genetic sources, leading to the conclusion that the presence of event deposits with marine sediments in the study area would be associated with tsunami inundation episodes. Based on 14C dating, the mean frequency of recurrence of tsunamis is estimated as 384 years (320–450 yr, 95% confidence interval) and a coefficient of variation of 0.78 (0.68–0.99, 95% confidence interval). The previously recorded limited paleotsunami evidence and absence of an estimated recurrence interval in the Shimokita Peninsula reaffirm the importance of Hachinohe as a tsunami record site for the activity of both trenches. [ABSTRACT FROM AUTHOR]

Intrinsic localized mode (ILM) can be generated in multiple mass‐spring systems using nonlinear springs, and ILM has attracted a lot of attention due to its special vibration modes that are not found in linear systems. However, the difficulty of creating nonlinearity remains a barrier to ILM research. In this paper, we propose a rotating magnetic spring based on magnetic nonlinearity. The nonlinear restoring properties of the proposed magnetic spring are confirmed by finite element method (FEA). Finally, using the restoring properties obtained from FEA, it is shown that ILM can be excited by MATLAB numerical analysis. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

France (CEA and FRAMATOME) and Japan (JAEA, MFBR, and MHI) teams have carried out collaborative works to have common technical views regarding a sodium-cooled fast reactor (SFR) concept. This paper mainly describes the capabilities of ASTRID 600 to demonstrate SFR technologies of both countries. Japan has studied the feasibility of an enhanced high burnup low-void effect (CFV) core and fuel using oxide dispersion-strengthened steel cladding in ASTRID 600, considering Japan's target for core performance. The neutronics design of the core has satisfied most required design targets and conditions. Regarding passive shutdown capabilities, Japan team has performed a preliminary numerical analysis for ASTRID 600 using a complementary safety device (CSD), called a self-actuated shutdown system (SASS), one of the safest approaches in Japan. Japan's team used the SASS in place of the hydraulically suspended absorber rod, called RBH, one of the safest approaches of France, to investigate the potential of the SASS as a design measure common to the countries. The preliminary analysis has shown that the SASS can satisfy the countries' main requirements. This study has also revealed that the mitigation measures of ASTRID 600 against a severe accident are promising to achieve in-vessel retention for both countries. [ABSTRACT FROM AUTHOR]

This study reports an ocean‐bottom pressure gauge (OBP) network, S‐net, which captured meteotsunamis with amplitudes as small as a few cm, and investigates its validity and limitation for meteotsunami research studies through data analyses and numerical simulations. On July 1, 2020, S‐net recorded tsunami‐like signals, although no earthquake was reported. These waves, propagating northward with a velocity of ∼110 m/s, were explained by an atmospheric low pressure with a maximum amplitude of −0.5 ± 0.1 hPa moving northeastward at a speed of 45–50 m/s. The maximum amplitudes of the sea‐surface height during the low‐pressure passing were up to twice larger than those directly converted from the ocean‐bottom pressure without considering the effect of the atmospheric pressure. Our results suggest that the S‐net with numerical simulations can detect the generation and propagation of meteotsunamis, which could not be achieved in the past when dense OBP networks were not available. Plain Language Summary: Recent developments in deep‐ocean tsunami observation networks using ocean‐bottom pressure gauge sensors have been remarkable, which have an advantage of continuously monitoring the ocean. On July 1, 2020, a deep‐ocean observation network off eastern Japan, S‐net, recorded small tsunami‐like ocean waves. Although tsunamis are often excited by earthquakes, no earthquake was reported at that time. We investigated the observed feature of these waves, which suggests that the waves were meteorological tsunamis, or meteotsunamis, originating from an atmospheric pressure disturbance. To investigate the behavior of these waves in detail, we conducted numerical meteotsunami simulations. The maximum amplitudes of the sea‐surface height during the atmospheric low‐pressure passing were up to twice larger than those expected from the observed seafloor pressure change without considering the contribution of the atmospheric pressure disturbance. We demonstrated that analyzing the data from the wide and dense array of S‐net made it possible to understand the behavior of the meteotsunamis in detail, which could not be achieved in the past when only a few pressure gauges were available. The S‐net's continuous monitoring of the seafloor pressure in the deep ocean will contribute to deepening our understanding of oceanography and meteorology. Key Points: Deep‐ocean pressure gauge array observation off NE Japan detected nonseismic tsunami‐like pressure signals with amplitudes of several hPaA numerical simulation revealed that the signals were meteotsunamis related to a northeastward‐moving atmospheric low pressureIt is necessary to consider the effects of the atmospheric pressure to appropriately estimate sea‐surface height from seafloor pressure gauge [ABSTRACT FROM AUTHOR]

The Higashi-Shikagoe limestone quarry is an open-pit mine situated in Hokkaido Prefecture, Japan, that has experienced four slope failure incidents since 1996. The rock slope behaviour has been monitored since the first failure event by measuring the rock slope surface displacement using an automated polar system. Recent measurements have revealed a gradual decrease of the distance between the beam generator and mirrors over time; however, the displacements and decrease rate differs between the centre and left- and right-hand sides of the quarry. This implies that the deformation characteristics of the rock slope and factors influencing the slope deformation differ at the centre and left- and right-hand sides of the quarry. In this study, the two-dimensional finite element method was used to identify the causes of slope deformation by investigating the effects of limestone excavation at the foot of the rock slope, the deterioration of a ∼70 m-thick clay layer at the rock slope foot wall, and shear failure owing to rainfall infiltration. The numerical results show that slope deformation on the left-hand side and centre of the quarry are induced by clay deterioration, whereas the right-hand side of the quarry is deformed owing to floor excavation and/or shear sliding. The rock slope is presently stable because the magnitude of the rate of displacement decrease is small and no acceleration is observed. [ABSTRACT FROM AUTHOR]

The world's first Liquefied Hydrogen (LH2) Carrier which will transport LH2 from Australia to Japan has been built. At Japanese port, reducing the tank pressure will be required for the safe tank operation. However, pressure reduction will cause flashing, leading to an excess of the venting capacity or liquid leakage. Hence, the purpose of this research is to clarify the pressure reduction rate and liquid behavior through experimental and numerical approaches respectively. Pressure reduction experiment under high liquid level condition was conducted by using 30 m3 tank filled with saturated LH2. The experiment showed that the pressure recovery occurred at the beginning of depressurization, and then the pressure decreased based on the equilibrium state. From numerical analysis by VOF based in-house CFD code, it was found that the pressure recovery was caused by the boiling delay, and the tank pressure followed the saturation pressure after the liquid fully stirred. • Pressure reduction experiment with large-scale LH2 tank was conducted under the high liquid level condition. • Pressure recovery occurred at the beginning of the experiment. • Based on thermodynamic analysis, pressure decreased following the equilibrium state after the pressure recovery. • The boiling delay caused the pressure recovery phenomenon. [ABSTRACT FROM AUTHOR]

Magnetic stimulation is widely used as a medical treatment for neurological diseases. A reduction in the size of magnetic stimulation devices is desirable, however, because the coils are relatively large compared with electrode stimulation devices. Furthermore, in transcranial magnetic stimulation, the exact magnetically evoked areas in the brain and the mechanisms of neural activation are largely unknown. This study aimed to develop a new implantable microcoil device that stimulates the brain locally, on the order of several tens of micrometers, as well as to understand the mechanisms of micromagnetic stimulation‐induced neural activity. First, to investigate the effects of microcoil shape on neural activation, the induced electric fields of semicircular microcoils with different diameters were calculated numerically in a microcoil model using the standard finite element method. Next, on the basis of the obtained numerical results from the microcoil model with different diameters, we compared the spatial properties of the possible activated areas in neural tissue and examined the most effective microcoil shape for neural activation. Finally, we measured microcoil‐evoked responses using autofluorescent flavoprotein imaging of the mouse brain in vivo, evaluated the validity of our proposed microcoil devices, and discussed possible future improvements for a chronic implant. © 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Tractor overturning is a leading cause of fatalities for farmers. In Japan, small tractors are used for farming on harsh terrain, such as slippery fields and steep passage slopes. On such potentially dangerous terrain, steering instability induced by bouncing and sliding can cause tractor overturning accidents. Steering instability can also deteriorate the precision of trajectory tracking in autonomous driving tractors. The present study numerically investigated tractor steering instability due to bouncing and sliding. A bouncing model and bicycle model were coupled based on Coulomb's classical theory of friction, and numerical experiments were conducted using the developed model. In the simulations, the tractor's travel velocity, the static friction coefficient, the bump length, and the turning radius were considered as control parameters. A turning test was conducted to investigate the basic steering performance of the developed model. The numerical results revealed that the bouncing and sliding caused by the disturbance exciter reduced the cornering force to zero, which led to a deviation of the turning trajectory from the desired trajectory. The tractor was then operated on a steep passage slope similar to those reported in accidents in Japan. In the simulation, bouncing and sliding occurred because of the steep slope. The results obtained in this study strongly suggest that bouncing and sliding occurring on specific terrain result in steering instability and are a major cause of overturning accidents. • A dynamic tractor model coupling a bouncing model and bicycle model was developed. • Steering instability induced by bouncing and sliding was investigated. • Intensive numerical experiments were conducted for various parameter combinations. • Bouncing and sliding reduced steering stability in numerical experiments. [ABSTRACT FROM AUTHOR]

Early estimation of biological growth of organisms is an indispensable task in ecology and related research areas. The biological growth is always time-continuous, while our observations of the phenomenon are time-discrete in practice. The formalism of the discrete costly observation (DCO) enables us to mathematically bridge the two qualitatively different processes. This formalism is still germinating, and its practical applications have not been carried out. This paper presents a first application of the DCO formalism to a cost-effective early estimation problem of the biological growth, and its mathematical and numerical analysis. Growth dynamics of organisms, which are fishery resources in this paper, is governed by a stochastic differential equation whose solution is observed discretely. The optimality equation to be solved for finding the most cost-effective observation policy is derived as a fixed point problem based on degenerate parabolic partial differential equations. The fixed point problem turns out to be uniquely solvable. A recursive approximation of the fixed point problem is presented and its solvability in a viscosity sense is discussed. A finite different scheme is then employed to fully-discretize the recursive equations. The present model is finally applied to a problem of Japanese smelt Plecoglossus altivelis altivelis (Ayu): an important inland fishery resource in Japan. [ABSTRACT FROM AUTHOR]

In recent years, liquefaction due to major earthquake caused serious damages to many infrastructures and houses around the world. In order to protect people's daily life and infrastructure from the disaster, development of effective and economical countermeasure against liquefaction that can be applied to existing houses is becoming increasingly important. Although many liquefaction countermeasures have been developed by many researchers, most of them require large construction machines and are costly, which limits their application to existing structures. For this reason, a liquefaction countermeasure, called as groundwaterlevel decreasing method, has been proposed in Japan. This method has already been put into practice and the construction of the countermeasure has finished several years ago. The purpose of this method is to change a liquefied layer to a non-liquefied layer by lowering the groundwater level. Yet the performance of this method has not been fully evaluated quantitatively. Therefore, in this paper, numerical analysis using FEM method was carried out to evaluate the liquefaction damage before and after the lowering of groundwater level. The calculation is conducted with 2D soil-water coupling finite element-finite difference (FE-FD) analysis based on a rotating-hardening elastoplastic constitutive model. From the analyses, it is found that the effective stress of the ground below under-groundwater level increases significantly because of the lowering of groundwaterlevel, resulting in an increase in resistance to liquefaction and mitigating the settlement damage of ground. [ABSTRACT FROM AUTHOR]

In this paper we define a line-cell conversion problem that has been reported as a new technical innovation in Japanese industry, and we construct a mathematical model to describe it. By numerical analysis of the model based on simulation experiments, we gain insight into line-cell conversion problems, such as (1) how many cells should be formatted, (2) how many workers should be assigned in each cell, and (3) how many workers should be rested on a shortened conveyor line when a conveyor assembly line is converted into cells, in order to optimise system performance, which is defined as the total throughput time and total labour power. Therefore, the model can be used as an evaluation tool in the case where (i) a company wants to change its production system (usually a belt conveyor line) to a new one (including cellular manufacturing), and (ii) a company wants to evaluate the performance of its converted system. [ABSTRACT FROM AUTHOR]

The purpose of our study is to (i) investigate the effects of the number of products, product attributes, and prices on consumer confusion, (ii) conduct a numerical analysis to check the robustness of the results, and (iii) present an example of the cell phone market in Japan. Following an ideal point model and embedding the number of products and product attributes, we clarify how these factors affect consumer confusion and purchase probability. We show that as the number of product attributes increases, the choice probability of each product becomes equal, implying that consumer confusion occurs. This result is robust to the introduction of prices as strategic variables. [ABSTRACT FROM AUTHOR]

In this paper, numerical modeling and analysis of a hybrid-spar floating wind turbine is presented. The hybrid-spar consists of steel at the upper part and precast prestressed concrete at the lower part. Such a configuration is referred to as a hybrid-spar in this paper. The hybrid spar was successfully installed offshore of Kabashima island, Goto city, Nagasaki prefecture, Japan, on Oct. 18, 2013 (see Utsunomiya et al., 2015, "Design and Installation of a Hybrid-Spar Floating Wind Turbine Platform," ASME Paper No. OMAE2015-41544 for details). In this paper, some details on numerical modeling of the hybrid-spar for design load analysis are presented. Then, the validation of the numerical analysis model is presented for a full-scale hybrid-spar model with 2-MW wind turbine. The comparison has been made for the natural periods and the response during rated power production test. Basically, both comparisons have shown good agreement between the measured values and the simulation, showing reliability of the developed code and the numerical model. [ABSTRACT FROM AUTHOR]

We performed kinetic studies of the growth of sulfate-reducing bacteria (SRB) indigenous to the water in an oilfield in Japan. The SRB growth was most active in injection water supplemented with ethanol; therefore, the SRB inhabiting the injection water of the reservoir were assumed to grow predominantly by assimilating sulfate and ethanol and generating H2S. Based on this mechanism and the results of incubation experiments in the injection water, we derived numerical models that calculate the growth rate and H2S generation of the SRB under three variables (temperature, sulfate concentration, and ethanol concentration). [ABSTRACT FROM AUTHOR]

Throughout history, large tsunamis have frequently affected the Sanriku area of the Pacific coast of the Tohoku region, Japan, which faces the Japan Trench. Although a few studies have examined paleo-tsunami deposits along the Sanriku coast, additional studies of paleo-earthquakes and tsunamis are needed to improve our knowledge of the timing, recurrence interval, and size of historical and pre-historic tsunamis. At Noda Village, in Iwate Prefecture on the northern Sanriku coast, we found at least four distinct gravelly sand layers based on correlation and chronological data. Sedimentary features such as grain size and thickness suggest that extreme waves from the sea formed these layers. Numerical modeling of storm waves further confirmed that even extremely large storm waves cannot account for the distribution of the gravelly sand layers, suggesting that these deposits are highly likely to have formed by tsunami waves. The numerical method of storm waves can be useful to identify sand layers as tsunami deposits if the deposits are observed far inland or at high elevations. The depositional age of the youngest tsunami deposit is consistent with the AD 869 Jogan earthquake tsunami, a possible predecessor of the AD 2011 Tohoku-oki tsunami. If this is the case, then the study site currently defines the possible northern extent of the AD 869 Jogan tsunami deposit, which is an important step in improving the tsunami source model of the AD 869 Jogan tsunami. Our results suggest that four large tsunamis struck the Noda site between 1100 and 2700 cal BP. The local tsunami sizes are comparable to the AD 2011 and AD 1896 Meiji Sanriku tsunamis, considering the landward extent of each tsunami deposit. [ABSTRACT FROM AUTHOR]

Earthquake is a threat to all kinds of structures including underground structures. Before the 1995 Hyogoken-Nanbu Japan earthquake, however, it was considered that underground structures are at minimum seismic risk in comparison to above-ground structures unless they are crossing the active faults. The collapse of Daikai station in the Kobe subway system during the 1995 Hyogoken-Nanbu earthquake exhibited that underground structures are at high risk of earthquake with shallow overburden. Though researches have been done on this issue, it is still necessary to investigate further the mechanical behavior of underground structure during an earthquake and corresponding efficient seismic enhancement. In this paper, in order to find out an optimum ground-improvement pattern for a rectangular-shaped box culvert constructed in soft ground that does not meet the present seismic requirement, numerical tests with nonlinear 2D/3D dynamic FEM are conducted. Different patterns of the ground improvement for the box curvet constructed with cut-and-cover method are investigated to find out an optimum pattern that can reduce the impact of earthquake in the most effective way. In the 2D/3D dynamic finite element analysis, the ground is Toyoura sand, typical clean sand, and its nonlinear mechanical behavior is described by Cyclic Mobility model. Validity of the proposed numerical method is firstly confirmed with 1 g shaking table test and then numerical tests are conducted to find out the optimum pattern for the ground improvement. Finally, an effective pattern of ground improvement for existing box culvert is proposed by the numerical analysis. [ABSTRACT FROM AUTHOR]

In light of the disastrous the 2011 Tohoku Pacific Earthquake, the government of Japan has conducted studies to revise the seismic design code, and elevated peak ground accelerations have been adopted. Consequently, revisions on existing design to comply with the updated code are required for public projects that are still undergoing. The design safety needs to be reassessed, and implementation of strengthening measures is required if deemed necessary. For liquefaction countermeasures, ground treatment techniques that could increase the density of soils are often the preferable alternatives. The treatment usually increases the in situ SPT-N or CPT-q values, which in turn would increase the resistance of soil against liquefaction. For many public infrastructures in Japan supported by bored piles embedded partly or entirely in sandy soils, reevaluation of design safety against soil liquefaction would be required. In an assessment of possible retrofitting countermeasures for an infrastructure foundation, ground treatment has been considered. In this case study, effect of ground treatment on response of piles in liquefiable soils was investigated with numerical analyses using FLAC. Results provide insights into this ground treatment effect and useful information for consideration in future design or decision making. [ABSTRACT FROM AUTHOR]

The multi-directional site response of a well-documented downhole array in Japan is numerically investigated with three directional (3-D) dynamic hydro-mechanically (HM) coupled Finite Element (FE) analysis. The paper discusses the challenges that 3-D modelling poses in the calibration of a cyclic nonlinear model, giving particular emphasis on the independent simulation of the shear and volumetric deformation mechanisms. The employed FE model is validated by comparing the predicted site response against the recorded motions obtained from the KiK-net downhole array monitoring system in Japan. The results show that, by employing the appropriate numerical model, a good agreement can be achieved between the numerical results and the monitored acceleration response in all three directions simultaneously. Furthermore, the comparison with the recorded response highlights the significance of the independent modelling of the shear and volumetric deformation mechanisms to the improvement of the numerical predictions of multi-directional site response. [ABSTRACT FROM AUTHOR]

Nankai megathrust earthquakes are expected to occur with a return period of approximately 90-200 years along the fault of the Nankai Trough. Because they are interplate earthquakes, it is predicted that they will cause heavy liquefaction damage as a result of the long duration of their ground motion, especially around bay areas with soft deposits. In this study, a numerical analysis was performed for the ground in Osaka City with a hypothetical earthquake in the Nankai Trough region. In the numerical simulation of the dynamic behavior, a liquefaction analysis program was used. To quantify the degree of liquefaction at certain points, an index, named the liquefaction risk index (LRI), was defined and obtained by the weighted integration of the effective stress-decreasing ratio (ESDR) with respect to depth. Moreover, the LRI values were evaluated by data from the 1995 Hyogoken-Nanbu earthquake. It was found that the obtained LRI values were greater than 6.0 for the points at which heavy liquefaction damage had occurred. From the numerical results, the risk of liquefaction was evaluated with these LRI values. [ABSTRACT FROM AUTHOR]

Ontake Volcano is located in central Japan, 200 km northwest of Tokyo and erupted on September 27, 2014. To study the structure of Ontake Volcano and discuss the process of its phreatic eruption, which can help in future eruptions mitigation, airborne electromagnetic (AEM) surveys using the grounded electrical-source airborne transient electromagnetic (GREATEM) system were conducted over Ontake Volcano. Field measurements and data analysis were done by OYO Company under the Sabo project managed by the Ministry of Land, Infrastructure, Transport and Tourism. Processed data and 1D resistivity models were provided by this project. We performed numerical forward modeling to generate a three-dimensional (3D) resistivity structure model that fits the GREATEM data where a composite of 1D resistivity models was used as the starting model. A 3D electromagnetic forward-modeling scheme based on a staggered-grid finite-difference method was modified and used to calculate the response of the 3D resistivity model along each survey line. We verified the model by examining the fit of magnetic-transient responses between the field data and 3D forward-model computed data. The preferred 3D resistivity models show that a moderately resistive structure (30-200 Ω m) is characteristic of most of the volcano, and were able to delineate a hydrothermal zone within the volcanic edifice. This hydrothermal zone may be caused by a previous large sector collapse. [ABSTRACT FROM AUTHOR]

In numerical models to simulate the dispersion of anthropogenic radionuclides in the marine environment, the sediment–seawater distribution coefficient ( K d ) for various elements is an important parameter. In coastal regions, K d values are largely dependent on hydrographic conditions and physicochemical characteristics of sediment. Here we report K d values for 36 elements (Na, Mg, Al, K, Ca, V, Mn, Fe, Co, Ni, Cu, Se, Rb, Sr, Y, Mo, Cd, I, Cs, rare earth elements, Pb, 232 Th and 238 U) in seawater and sediment samples from 19 Japanese coastal regions, and we examine the factors controlling the variability of these K d values by investigating their relationships to hydrographic conditions and sediment characteristics. There was large variability in K d values for Al, Mn, Fe, Co, Ni, Cu, Se, Cd, I, Pb and Th. Variations of K d for Al, Mn, Fe, Co, Pb and Th appear to be controlled by hydrographic conditions. Although K d values for Ni, Cu, Se, Cd and I depend mainly on grain size, organic matter content, and the concentrations of hydrous oxides/oxides of Fe and Mn in sediments, heterogeneity in the surface characteristics of sediment particles appears to hamper evaluation of the relative importance of these factors. Thus, we report a new approach to evaluate the factors contributing to variability in K d for an element. By this approach, we concluded that the K d values for Cu, Se, Cd and I are controlled by grain size and organic matter in sediments, and the K d value for Ni is dependent on grain size and on hydrous oxides/oxides of Fe and Mn. [ABSTRACT FROM AUTHOR]

The email and affiliation of co-author Daisuke NOHARA is wrong in the original article. Now the email has been corrected to "noharad@kajima.com" and the affiliation has been corrected to "Sustainable Society Laboratory, KAJIMA Technical Research Institute, Tobitakyu 2-19-1, Chofu 182-0036, Japan". [ABSTRACT FROM AUTHOR]

Strong stratification has formed in Lake Abashiri, a typical meromictic lake in Hokkaido, in the subarctic zone in Japan. When the anoxic water of the lower layer is upwelled to the surface by a strong wind, fish and corbicula clams die due to a lack of dissolved oxygen. This event is called as blue tide. It was observed that the dissolved methane in the lake decreased more than 100 t after the blue tide which occurred in 2008. This is the discovery of the phenomenon that a large quantity of methane diffuses to the atmosphere caused by upwelling of anoxic water which contains dissolved methane. We named the event as "methane burst". It is also the first report that the wind-driven upwelling is reproduced using a numerical analysis code and the methane burst is analyzed. During this blue tide, the methane flux was approximately 170 times greater than usual. [Display omitted] • A 3D numerical model estimated methane diffusion in a brackish lake. • Strong wind caused a massive methane burst into the atmosphere. • Stratification suppressed methane flux to the atmosphere. [ABSTRACT FROM AUTHOR]

To partition evapotranspiration (ET) into soil evaporation ( E ) and vegetation transpiration ( T ), a new numerical Iso-SPAC (coupled heat, water with isotopic tracer in soil–plant–atmosphere-continuum) model was developed and applied to a temperate-grassland ecosystem in central Japan. Several models of varying complexity have been tested with the aim of obtaining the close to the true value for the isotope composition of leaf water and transpiration flux. The agreement between model predictions and observations demonstrated that the Iso-SPAC model with a steady-state assumption for transpiration flux can reproduce seasonal variations of all the surface energy balance components as well as isotope data (canopy foliage and ET flux). Uncertainties/errors for T/ ET and each end members in assigned model parameters and measured input variables were discussed quantitatively. The T/ ET increased with grass growth, and the sharp reduction caused by clear cutting was well reflected. The transpiration fraction ranged from 0.02 to 0.99 during growing seasons, and the mean value was 0.75 with a standard deviation of 0.24. Results indicate that SPAC model is a promising tool for integrating the isotopic fractionation processes with separate E and T in multispecies terrestrial ecosystems and has the advantage of enabling long-term assessment of ET partitioning as well as isotopic enrichment output at soil–plant–atmosphere interface. Our study reemphasize that isotope tracer approach is useful for evaluating quantitatively the relationships among hydrological components. [ABSTRACT FROM AUTHOR]

We conducted numerical simulations of a repeating earthquake sequence on the plate boundary off the shore of Kamaishi, northeastern Japan, assuming rate- and state-dependent friction laws. Uchida et al. 2014 reported that the Kamaishi repeating earthquakes showed an increase in magnitude and a decrease in recurrence interval after the 2011 Tohoku-oki earthquake ( M 9), but an approximately constant magnitude ( M ~ 4.9) and a regular recurrence interval (~ 5.5 years) before the Tohoku-oki earthquake. A M 5.9 event occurred just after the M 9 event, and was followed by a M 5.5 event. We considered a fault patch of velocity-weakening friction, with frictional parameters leading to seismic slip confined in its central part of the patch. Afterslip due to the M 9 event was involved in the model to increase the loading rate on the patch. The simulation successfully reproduced increasing magnitude and decreasing recurrence time caused by the afterslip. A M 6 class event, in which seismic slip spread over the entire area of the patch, occurred just after the M 9 event for the aging law and the Nagata law. When we assumed the aging law with frictional parameters which lie near the boundary between leading to slip on the entire patch and slip confined in its central part, the M6 class event was followed by a M 5.5 class event. Furthermore we examined a conditionally stable large patch that contained a small unstable patch. This model also reproduced a M 6 class event after the M 9 event. In these models, stress outside the confined area of the path is released before a dynamic event under a constant low loading rate, whereas the stress perturbation due to afterslip within the seismic cycle induces a dynamic event on the entire patch. [ABSTRACT FROM AUTHOR]

Numerical modeling of sediment transport on the Sendai Plain in northeast Japan, which was caused by the 2011 Tohoku-oki tsunami, was performed to investigate why onshore tsunami deposits included small amounts of marine materials and to explain the gap between the maximum inland extent of the recognizable sand layer and the limit of inundation. The simulation results generally corresponded with the thicknesses of the deposits observed in the field by previous studies. The simulation revealed that the tsunami caused a significant amount of erosion on the beach and in the coastal forest; however, erosion was significantly limited on the offshore seafloor. In addition, the bore of the highest tsunami wave offshore limited the amount of suspended sediment due to a steep bathymetric profile of the shoreface and a moderate initial drop in water level prior to the arrival of the bore. This resulted in limited suspension and shoreward advection of the sediments and a minor contribution of the seafloor sediments to the onshore tsunami deposit. Visualization of the onshore sediment transport indicated that the sediment transport was significantly affected by artificial topographic features. The flow speed and height varied across the topographic highs, and sediments were trapped on the seaward side of these highs. In coastal areas, the sediment supply was limited due to the presence of engineered dikes along the coast. In inland areas, embankments of paved roadways caused increased deposition on the seaward sides of the embankments and less deposition on the leeward sides of the embankments. Although some aspects of the relevant physics were not fully implemented in the model, in which uncertainties exist, the results may explain the processes and consequences of sedimentation from a tsunami event. [ABSTRACT FROM AUTHOR]

We investigate the size of primary balance that can be sustained and the change in public debt and physical capital under transition dynamics in the Japanese economy. For our investigation, we construct a simple overlapping generations model. We find that a large primary surplus, 13.8–18.7% of GDP, is needed to prevent the public debt-to-GDP ratio from diverging infinitely. We also show that even if the large primary surplus can be maintained, the Japanese economy faces a sharp reduction in physical capital from 191 to 70.0% of GDP on the transition path. [ABSTRACT FROM AUTHOR]

Iron requirements were estimated from the results of the National Health and Nutrition Surveys of Japan 2003–2007 using the numerical analysis of requirements based on an integral equation. The numerical analysis used population-based data on iron nutriture, the prevalence of inadequate iron status, and the distribution of iron intakes. The cutoff value for inadequate iron status was defined as a serum ferritin concentration <30 ng/mL. Iron intakes and menstrual blood losses followed a log-normal distribution and published values were corrected accordingly to calculate usual values. For women aged 18–29 years old, the median of the estimated median iron requirement (corresponding to the estimated average requirement by using the terminology of the dietary reference intakes) was 7.59 mg (range, 6.86–8.11). The median of the estimated usual iron intake covering the needs of women with 80 mL per cycle of menstrual blood loss was 11.27 mg (range, 10.16–12.00), and the median of the usual iron intake covering the needs of 97.7% of women was 13.93 mg (range, 12.55–14.81). For women aged 30–49 years old, the corresponding figures were 8.13 mg (range, 7.96–8.69), 11.95 mg (range, 11.72–12.77), and 14.71 mg (range, 14.44–15.72). [ABSTRACT FROM AUTHOR]

Abstract: As temporary structures, steel-sheet-pile-quay (SSPQ) retaining walls have been widely used to counteract excavation problems in Japan not only in urban areas, but also in mountainous areas. The most important features of retaining walls are that they are easy to install in any narrow space, they can be reused many times in different types of soil and, above all, they are strong enough to resist any kind of earth pressure. The shortcoming of retaining walls, however, is that the deformation of the structures may sometimes be rather large, which might become an obstacle for geotechnical engineers wanting to use them as permanent structures. In this paper, centrifuge model tests [1] on the seismic performance of SSPQ retaining walls are simulated systematically with a two-dimensional (2D) dynamic analysis using the finite element method (FEM). In the centrifuge model tests, an SSPQ retaining wall subjected to five consecutive seismic waves is considered. To analyze the influence of the soil density on the performance of the retaining wall and the ground, a middle dense Toyoura sand ground (D r =60%) and a dense Toyoura sand ground (D r =75%) are used. In the analysis, the seismic behavior of the SSPQ retaining wall and the surrounding ground are described separately by beam elements and a cyclic mobility model in which the stress-induced anisotropy, the density and the structure of the ground can be described in a unified way. In order to clarify the influence of the fixed boundary adopted in the centrifuge model vibration tests, an analysis in prototype scale, that completely corresponds to the conditions of the centrifuge model tests, and an analysis in full scale, that corresponds to the real ground conditions, are carried out. By comparing the calculated results with the results of the centrifuge model vibration tests, the anti-seismic capacity of the SSPQ retaining wall and the dynamic performance of the ground during earthquakes are discussed in detail. The accuracy of the evaluation method using FEM is also verified. The purpose of this study is to establish an evaluation approach for the seismic behavior of SSPQ retaining walls as permanent earth-balanced structures. [Copyright &y& Elsevier]

The article considers optimization of mixed constraints for a controlled system that describes countrylevel economic growth driven by technological progress. An algorithm is proposed, reducing this problem to an equivalent general optimization problem in a normed space, which in turn is solved by an iterative method based on N. N. Krasovskii's extremal shift method. Calculation results are reported for the economy of Japan in the second half of the twentieth century. [ABSTRACT FROM AUTHOR]

Abstract: Protracted recession in Japan for the last twenty years is characterized by persistent deflation and negative output gap. Recently, Inoue et al. presented the concept of “trap of credit creation” which represents mechanism of the persistent deflation based on zero-interest-rate economy. Three new Keynesian DGE models by Inoue et al. explain this type of deflation as a steady state of a system. The DGE models, which are based on optimization for utility function, derive simultaneous nonlinear differential equations. In the present paper, we study dynamical features on the steady states of the three DGE models (i.e. Model I, II, and III), using numerical calculation: i.e. we analyze stability of steady states, using Jacobian matrices. Model I and II correspond to models for positive-interest-rate economy, and Model III suggests mechanism of the recession characterized as trap of credit creation under zero-interest-rate economy. We show each of the models have a stable steady state. This result supports adequacy of the present models, which can shed light on mechanism of the protracted recession. [Copyright &y& Elsevier]

Pu contamination originating from Fukushima accident has not been detected in marine sediment samples collected outside a 30 km circle around the plant. It is shown, by means of numerical modelling, that if any impact from the accident has occurred, this would remain in a very close area to Fukushima because of the low Pu mobility in the marine environment. Since the situation inside the 30 km zone remains unknown, further studies on the determination of Pu isotopes in sediments within this area are required. [ABSTRACT FROM AUTHOR]

During the devastating 11 March 2011 Japanese tsunami, data from two tsunami detectors were used to determine the tsunami source within 1.5 h of earthquake origin time. For the first time, multiple near-field tsunami measurements of the 2011 Japanese tsunami were used to demonstrate the accuracy of the National Oceanic and Atmospheric Administration (NOAA) real-time flooding forecast system in the far field. To test the accuracy of the same forecast system in the near field, a total of 11 numerical models with grids telescoped to 2 arcsec (~60 m) were developed to hindcast the propagation and coastal inundation of the 2011 Japanese tsunami along the entire east coastline of Japan. Using the NOAA tsunami source computed in near real-time, the model results of tsunami propagation are validated with tsunami time series measured at different water depths offshore and near shore along Japan's coastline. The computed tsunami runup height and spatial distribution are highly consistent with post-tsunami survey data collected along the Japanese coastline. The computed inundation penetration also agrees well with survey data, giving a modeling accuracy of 85.5 % for the inundation areas along 800 km of coastline between Ibaraki Prefecture (north of Kashima) and Aomori Prefecture (south of Rokkasho). The inundation model results highlighted the variability of tsunami impact in response to different offshore bathymetry and flooded terrain. Comparison of tsunami sources inferred from different indirect methods shows the crucial importance of deep-ocean tsunami measurements for real-time tsunami forecasts. The agreement between model results and observations along Japan's coastline demonstrate the ability and potential of NOAA's methodology for real-time near-field tsunami flooding forecasts. An accurate tsunami flooding forecast within 30 min may now be possible using the NOAA forecast methodology with carefully placed tsunameters and large-scale high-resolution inundation models with powerful computing capabilities. [ABSTRACT FROM AUTHOR]