Large kinetic power in FRII radio jets

We investigate the total kinetic powers (L _j) and ages (t _age) of powerful jets of four FR II radio sources (Cygnus A, 3C 223, 3C 284, and 3C 219) by the detail comparison of the dynamical model of expanding cocoons with observed ones. It is found that these sources have quite large kinetic powers with the ratio of L _j to the Eddington luminosity (L _Edd) resides in 0.02<L _j/L _Edd<10. Reflecting the large kinetic powers, we also find that the total energy stored in the cocoon (E _c) exceed the energy derived from the minimum energy condition (E _min): 2<E _c/E _min<160. This implies that a large amount of kinetic power is carried by invisible components such as thermal leptons (electron and positron) and/or protons.     

Simple monitoring method for precaution of landslides watching tilting and water contents on slopes surface

A low-cost and simple monitoring method for early warning of landslides is proposed. To detect abnormal deformation of a slope, this method employs a tilt sensor in place of an extensometer on the slope surface. In order to examine the relevance of measuring rotation angle on a slope surface by tilt sensor, model tests were conducted, and rotation on the slope surface was observed together with slide displacement along the surface. The rotation data responded 30 min before failure in a model test, which could be useful as a signal for early warning. However, the behavior of rotation before failure varies from case to case, and thus, criteria to issue warning should be defined more carefully. For a model slope made of uniform loose sand, measurement of slide displacement along the slope surface is sensitive to failure at the toe, while the measurement of rotation on the slope surface is useful to detect the development of progressive failure upward along the slope. Wireless sensor units with microelectromechanical systems (MEMS) tilt sensor and volumetric water content sensor were also examined on a real slope in Kobe City, and a long-term monitoring was attempted. A simple but possible way to define the criteria of judgment to issue warning can be proposed based on combination of data obtained by the tilt sensors and volumetric water content sensors.     

Present environment of Dam Lake Sambe,southwestern Japan: a geochemical study of bottom sediments

Geochemical analyses of lakebed and core sediments from Lake Sambe on the outskirts of Oda City in Shimane prefecture in southwestern Japan were carried out in order to assess the water quality and the concentration and distribution patterns of sixteen elements. The lake water showed a stratified condition with respect to dissolved O₂, and As, Fe, and Mn concentrations in the bottom layers which increased in the summer. The chemical composition of the sediments, as measured by X-ray fluorescence, included major and trace elements (P, Ca, Sc, Ti, V, Cr, Fe, Ni, Cu, Zn, As, Sr, Zr, Pb, and Th), and total sulfur (TS). Elevated values of As, Zn, V, Fe, P, and TS were present in several layers of the upper cores (from 0 to 5 cm) and other surface sediments. Increases in the abundances of these metals in lake sediments are probably related to the reducing condition of the sediments, fine-grained organic rich sediments, and post-depositional diagenetic remobilization. Moreover, correlations between the concentrations of trace metals and iron in the sediments suggest their adsorption onto Fe (oxy)hydroxides, whereas correlations with sulfur indicate that they were precipitated as Fe-sulfides. The average abundances of As, Pb, Zn, and Cu exceeded the lowest effect level and Interim Sediment Quality Guideline values that the New York State Department of Environmental Conservation and the Canadian Council of Ministers of the Environment determined to have moderate impact on aquatic organisms. In addition, concentrations of As and Zn exceeded the Coastal Ocean Sediment Database threshold value, indicating potentially toxic levels. Therefore, the presence of trace metals in the lake sediments may result in adverse effects on biota health.     

Identification of soil–structure interaction effect in base-isolated bridges from earthquake records

Identification of system parameters with the help of records made on base-isolated bridge during earthquakes provides an excellent opportunity to study the performance of the various components of such bridge systems. Using a two-stage system identification methodology for non-classically damped systems, modal and structural parameters of four base-isolated bridges are reliably identified using acceleration data recorded during 18 earthquakes. Physical stiffness of reinforced concrete columns, dynamic properties of soil and foundation impedance are found by available theoretical models in conjunction with pertinent information from the recorded accelerographs. Soil–structure interaction (SSI) effect in these bridges is examined by comparing the identified and physical stiffness of the sub-structure components. It is found that SSI is relatively pronounced in bridges founded in weaker soils and is more strongly related to the ratio of pier flexural stiffness and horizontal foundation stiffness than soil shear modulus, G_s, alone. However, substantial reduction in G_s is observed for moderate seismic excitation and this effect should be taken into account while computing foundation impedance.     

The properties of tuned liquid dampers using a TMD analogy

Liquid motions in shallow Tuned Liquid Dampers (TLDs) with rectangular, circular, and annular tanks, subject to harmonic base excitation, are measured experimentally. Using a Single-Degree-of-Freedom (SDOF) Tuned Mass Damper (TMD) analogy, equivalent mass, stiffness and damping of the TLD are calibrated from the experimental results. These parameters are functions of the TLD base amplitude. Some important properties of the TLD are discussed on the basis of these results.     

Shifting of the volcanic fronts during Early to Late Miocene in the Northeast Japan arc

Abstract Recent advanced chronological studies for the Tertiary volcanic rocks from the Northeast (NE) Japan arc revealed three volcanic fronts which differed in temporal and spatial distribution. These fronts were (i) the Matsumae-Shizukuishi-Shiogama line of 22–25 Ma which is obliquely across the Quaternary volcanic front (QVF); (ii) the Tomari-Shiogama line of 13–16 Ma which exists 30–50 km east of the QVF and (iii) a line of 0–8 Ma which is the same as the QVF. The first shifting of the 22–25 Ma line to the 13–16 Ma one was due to the counterclockwise rotation of the NE Japan arc during 20–12 Ma as proposed by Otofuji et al . (1985), and the second shifting of the 13–16 Ma line to the 0–8 Ma line could have contributed to a decrease in the dip of the slab of the Pacific plate which subducted beneath the NE Japan arc during 13–8 Ma.     

Design formulas for tuned mass dampers based on A perturbation technique

Modal properties of tuned mass damper (TMD)-structure two-degree-of-freedom (2DOF) linear systems are studied employing a perturbation technique. Using the perturbation solutions, formulas relevant to designing the TMD for various types of loading are obtained; they are expressed as a function of mass ratio, tuning ratio, damping ratio of the TMD and damping ratio of the structure. Equivalent additional dampings of the structure due to the TMD are derived for random and harmonic forces. Matched expressions of equivalent damping, which are valid for detuned, i.e. non-optimal, conditions are also presented. The stability boundary of TMD-structure systems subject to linear self-excited forces is derived in a closed form. Using the perturbation solutions, procedures for optimizing the TMD parameters for various types of loading are explained and the optimal values are derived. The formulas obtained in this study can be used with good accuracy for mass ratios less than 0.02.     

Seismic response controlled structure with Active Variable Stiffness system

The Active Variable Stiffness (AVS) system is proposed as a seismic response control system. It actively controls structural characteristics, such as stiffness of a building, to establish a non-resonant state against earthquake excitations, thus suppressing the building's response. It consumes a relatively small amount of energy and maintains the safety of the building in moderate to severe earthquakes. In order to accumulate practical data and investigate them, a building has been constructed as a trial. This paper describes the applied system, the control algorithm, verification of stiffness selection, results of tests for verifying system characteristics, some observed earthquake records and simulation analyses. Responses in controlled and uncontrolled states have been compared to show the effectiveness of the proposed system.     

High temperature creep of single crystal gadolinium gallium garnet

High temperature creep of single crystal gadolinium gallium garnet (GGG) was studied in the temperature range of 1723–1853 K (0.86–0.94 T_m, T_m: melting temperature) and strain rate from 9 · 10^?7 s^?1 to 2 · 10^?5 s^?1. The compression tests were made along the 〈100〉 and 〈111〉 orientations. We have performed both constant strain-rate and stress-dip tests. For the 〈100〉 orientation, deformation occurs via the 〈111〉 slip systems. For the 〈111〉 orientation, both the 〈100〉 {010} and the 〈111〉 slip systems can be activated. GGG garnet is very strong under these conditions: σ/μ=(1–3)×10^?3 (σ: creep strength, μ: shear modulus). The creep behavior is characterized by a power law with stress exponent n=2.9–3.3 and high activation energies E^*=612–743 kJ/mol (E^*～45×RT_m, at zero stress which decrease with the increase of stress). Stress-dip tests suggest a small internal stress (σ_i/σ～0.62; σ_i: internal stress, σ: applied stress) compared to other materials. These results suggest that the high creep strength of GGG is mainly due to difficulty of dislocation glide rather than dislocation climb.     

1986 Values for Fifteen GSJ Rock Reference Samples, "Igneous Rock Series"

During the five-year period (April 1981 - March 1986), a series of fifteen rock reference samples, "Igneous rock series", has been prepared by the Geological Survey of Japan (GSJ). Based on the data available (published and communicated), consensus values for major, minor and trace elements have been derived; these values are presented for this second series of samples as well as for the first series of two samples, Granodiorite JG-1 and Basalt JB-1.