Basic Study on Detection of Deteriorated RC Structures Using Infrared Thermography Camera

Infrastructures in the world get old in several decades of their service time. Falling-offs of parts of deteriorated structures were often reported and sometimes caused casualties in Japan and many other countries. When an earthquake occurs, in particular, deteriorated structures have higher possibility to be damaged or collapsed. Thus assessing the health condition of structures is one of the important topics in civil engineering. Considering a large number of structures that have been in service more than 40 years in Japan, efficient evaluation methods are requested. In this regard, non-destructive tests have high possibility to be applied to various structures without affecting their functions. Accordingly, this study focuses on the use of infrared thermography to detect internal deterioration of concrete structures. As a first step of investigation, thermography diagnosis, hammer sounding test and Schmidt rebound hammer test were carried out to detect internal deterioration of a concrete retaining wall located in the campus of Chiba University, Chiba, Japan, and the results were compared to evaluate the capability and accuracy of these diagnosis methods

Soil Amplification Based on Array Observation in Chiba, Japan

The amplification characteristics of earthquake ground motion were investigated based on the Chiba Array observation records. The amplification of peak acceleration occurred mostly at the top soft layer and is similar for the three ground motion components. The ensemble Fourier spectrum ratio and coherence function were calculated and the amplification can be clearly seen in them. The drop of the coherence function at natural frequencies was discussed. The Fourier spectrum ratio and coherence function were also obtained using the smoothing procedure and were compared with those of the ensemble. Microtremor was measured at 11 points corresponding to the location of the surface accelerometers. The power spectrum of microtremor was compared with that of the earthquake ground motion for different points and for different events. Emphasis has been placed on knowing the property of the peaks appearing in the power spectra

Development of Supreme Super High-Density Realtime Disaster Mitigation System for Gas Supply System

With the 3,700 New SI sensors installed throughout its service area (3,100 km2), Tokyo Gas has started to develop its super high-density real-time disaster mitigation system SUPREME for gas supply systems. Immediately after an earthquake, seismic data from the New SI sensors is relayed to the main system where extremely precise estimates of the damage are made on the spot. Damage estimation consists of making an estimate of the surface distribution of seismic motion that takes account of the site amplification factor, and making an estimate of damage to the pipeline network that takes account of factors such as the types of the pipes, the topography of the area, and the liquefaction conditions

Quantum algorithm for collisionless Boltzmann simulation of self-gravitating systems

The collisionless Boltzmann equation (CBE) is a fundamental equation that governs the dynamics of a broad range of astrophysical systems from space plasma to star clusters and galaxies. It is computationally expensive to integrate the CBE directly in a phase space, and thus the applications to realistic astrophysical problems have been limited so far. Recently, Todorova \& Steijl (2020) proposed an efficient quantum algorithm for solving the CBE with a significantly reduced computational complexity. We extend the method to perform quantum simulations that follow the evolution of self-gravitating systems. We first run a 1+1 dimensional test calculation of free streaming motion on 64$\times$64 grids using 13 simulated qubits and validate our method. We then perform simulations of Jeans collapse, and compare the result with analytic and linear theory calculations. We propose a direct method to generate initial conditions as well as a method to retrieve necessary information from a register of multiple qubits. Our simulation scheme achieves $\mathcal{O}(N_v^3)$ less computational complexity than the classical method, where $N_v$ is the number of discrete velocity grids per dimension. It will thus allow us to perform large-scale CBE simulations on future quantum computers.Comment: 10 pages, 9figure

Seismic microzonation of Hanoi, Vietnam using microtremor observations

It is imperative to carry out comprehensive seismic hazard assessment for big cities in order to reduce the potential damage from earthquakes. One of the fundamental steps in seismic hazard assessment is microzonation of cities, which provides a basis for site-specific hazard analysis. This study focuses on microzonation of Hanoi, the capital city of Vietnam, using microtremor observations. Microtremor observations were carried out at 63 sites in Hanoi. The predominant period of the ground at all the sites were determined from the horizontal to vertical (H/V) spectral ratios of microtremors and a microzonation map was developed for Hanoi on the basis of the variation of the predominant period of the ground. It was observed that in Hanoi, the northern part of the city has shorter predominant period (less than 0.4 s) and the predominant period of the ground increases towards south. The areas in the Hanoi metropolitan area, especially areas located along the Red River and around the West Lake have comparatively longer predominant period (0.6-1.0 s). The western districts of Hanoi also have longer predominant period (0.6-1.2 s) and it decreases towards the eastern direction. This study shows that there is a possibility of long-period ground motion in Hanoi, especially in Hanoi metropolitan area and western and southern districts of Hanoi. The long-period ground motion may have severe effects on high-rise buildings and other long-period structures

Giant flare of SGR 1806-20 from a relativistic jet

Japanese magnetospheric explorer GEOTAIL recorded a detailed light curve during the initial 600 msec of a giant flare from SGR 1806-20 on December 27, 2004. We show that the observed light curve is well explained by an emission from relativistically expanding fireballs, like those of gamma-ray bursts (GRBs). Especially, the observed rapid fading after 500msec suggests that ejecta is collimated in a jet. We derive an upper limit on the jet opening half-angle of 0.2 radian that is as narrow as those of GRBs.Comment: 4 pages, 2 figures, accepted by Publications of the Astronomical Society of Japan (PASJ

Use of Microtremors for the Estimation of Ground Vibration Characteristics

Short-period micro tremor array observation is conducted at five sites in the Tokyo Metropolitan area of Japan. The Fourier spectra of horizontal and vertical components show variations in time, but their ratio is stable for different time instants. The characteristics of the amplitude ratio are similar to that of Rayleigh wave and the period correspond to the peak ratio correspond to the predominant period of the sites for shear wave propagation. A parametric study for two-layered models reveals that the peaks for Rayleigh wave and shear wave are close for the ground having large impedance ratio. The F-K spectrum analysis using vertical components obtained the phase velocity close to the dispersion curve for the Rayleigh wave

Quantum algorithm for the Vlasov simulation of the large-scale structure formation with massive neutrinos

Miyamoto K., Yamazaki S., Uchida F., et al. Quantum algorithm for the Vlasov simulation of the large-scale structure formation with massive neutrinos. Physical Review Research 6, 013200 (2024); https://doi.org/10.1103/PhysRevResearch.6.013200.Investigating the cosmological implication of the fact that neutrino has finite mass is of importance for fundamental physics. In particular, massive neutrino affects the formation of the large-scale structure (LSS) of the universe, and, conversely, observations of the LSS can give constraints on the neutrino mass. Numerical simulations of the LSS formation including massive neutrino along with conventional cold dark matter is thus an important task. For this, calculating the neutrino distribution in the phase space by solving the Vlasov equation is a suitable approach, but it requires solving the PDE in the (6+1)-dimensional space and is thus computationally demanding: Configuring ngr grid points in each coordinate and nt time grid points leads to O(ngr6) memory space and O(ntngr6) queries to the coefficients in the discretized PDE. We propose a quantum algorithm for this task. Linearizing the Vlasov equation by neglecting the relatively weak self-gravity of the neutrino, we perform the Hamiltonian simulation to produce quantum states that encode the phase-space distribution of neutrino. We also propose a way to extract the power spectrum of the neutrino density perturbations as classical data from the quantum state by quantum amplitude estimation with accuracy ϵ and query complexity of order Õ[(ngr+nt)/ϵ]. Our method also reduces the space complexity to O[polylog(ngr/ϵ)] in terms of the qubit number, while using quantum random access memories with O(ngr3) entries. As far as we know, this is the first quantum algorithm for the LSS simulation that outputs the quantity of practical interest with guaranteed accuracy

Induction of fatty liver by Coleus forskohlii extract through enhancement of de novo triglyceride synthesis in mice

AbstractColeus forskohlii extract (CFE), an herbal ingredient, is used for weight-loss products. CFE's alleged efficacy is attributed to forskolin. However, CFE has been shown to induce fatty liver in mice, with components other than forskolin playing a part in this effect. The present study addressed the underlying mechanism of CFE-induced fatty liver by analyzing changes in CFE-treated mice of lipid concentrations and of the levels of mRNAs encoding enzymes and transcription factors known to be related to fatty liver. Mice were fed a diet containing 0, 0.3 and 1% CFE for 2 weeks. CFE at 1% clearly induced fatty liver, as demonstrated by histological examination and confirmed by increases in triglyceride concentrations in liver. However, treated mice did not exhibit elevation in plasma levels of non-esterified fatty acids. Comprehensive analysis of liver mRNA levels revealed accumulation of multiple transcripts, including mRNAs encoding enzymes acetyl-CoA carboxylase and long-chain elongase; transcription factor peroxisome proliferator-activated receptor gamma (PPARγ); and lipid-droplet-associated fat-specific protein 27 (Fsp27). These findings suggest that the de novo synthesis and accumulation of triglyceride in the liver, through the enhanced expression of specific lipogenic mRNAs, is a major underlying mechanism of fatty liver induction by CFE

TeV Gamma-Rays from Old Supernova Remnants

We study the emission from an old supernova remnant (SNR) with an age of around 10^5 yrs and that from a giant molecular cloud (GMC) encountered by the SNR. When the SNR age is around 10^5 yrs, proton acceleration is efficient enough to emit TeV gamma-rays both at the shock of the SNR and that in the GMC. The maximum energy of primarily accelerated electrons is so small that TeV gamma-rays and X-rays are dominated by hadronic processes, pi^0-decay and synchrotron radiation from secondary electrons, respectively. However, if the SNR is older than several 10^5 yrs, there are few high-energy particles emitting TeV gamma-rays because of the energy loss effect and/or the wave damping effect occurring at low-velocity isothermal shocks. For old SNRs or SNR-GMC interacting systems capable of generating TeV gamma-ray emitting particles, we calculated the ratio of TeV gamma-ray (1-10 TeV) to X-ray (2-10 keV) energy flux and found that it can be more than ~10^2. Such a source showing large flux ratio may be a possible origin of recently discovered unidentified TeV sources.Comment: 10 pages, 6 figures, 2 tables, MNRAS in pres