New Trends in the Zee Model

Recent trends in the Zee model are reviewed. Especially, the importance of a serious constraint in the Zee model, sin^2 2\theta_{solar} =1.0, is pointed out.Comment: 3 pages, Latex, Plenary talk given at NuFact'01 (held in Tukuba, Japan, 24-30 May 2001), to appear in the Proceeding

On the Vibrational Spectrum and the Vibrational Specific Heat of a Binary Superlattice Alloy

The change in the vibrational modes of a binary superlattice alloy due to the change in its own degree of order has previously been discussed. It was then expected that the vibrational specific heat of the superlattice alloy would change in response to the change in its own degree of order. Using the result obtained formerly, we have applied, in the present paper. Houston\u27s approximate method of finding the frequency distribution function N(ν) to the calculation of the vibrational specific heat of β-brass in the state of any specified degree of order. It is shown that the vibrational specific heat of the disordered alloy is generally larger than that of the ordered one at oridnary temperatures. If two kinds of atoms which are the components of alloy are nearly equal in mass, the vibrational specific heat of the ordered alloy becomes larger than that of the disordered one at low temperatures

On the Nonuniformity in Fluidized Bed

Mean (μc) and variance (σ) of local particle concentration in fluidized bed were measured by capacitance probe method using integrator and vacuum tube thermocouple. Particle concentration in bubble and dense phases (cb and cd), rise velocity of bubble (ub), bubble thickness (y) and its frequency (f) were also measured from the signal current recorded on oscillograms. The effects of fluidizing conditions on μc and σ were studied. In the bulk of bed, μc remains at a value fixed by the fluidizing conditions. It decreases with air velocity. σ, on the other hand, increases with probe level up to considerably higher portion of bed and there arrives at a constant value which increases with bed height and air velocity. The following equation was introduced to represent μc by the fluidizing characteristics. μc=yf/ubcb+(1-yf/ub)cd μc calculated by this equation coincides well with the measured μc. A regression equation of σ upon fluidizing characteristics, σ=0.72{yf/ub(1-yf/ub)}⁰.⁴⁶(cd-cb)².⁸⁹ was obtained, and the statistical analyses on this equation revealed that σ changes chiefly with (cd-cb), and accordingly, σ represents the nonuniformity in fluidized bed mainly in the form of particle concentration difference between bubble and dense phases

Emission from C-, N- and O-Impurity Ions in Linear Pinch He Plasma in Vaccum Ultraviolet λ500 to 1,500A Region

The He plasma containing C-and O-impurity ions or N-impurity ions, whose electron density and temperature ranged from 5 × 10¹⁷ to 3 × 10¹⁸cm⁻³ and from 4 to 5 eV, respectively, was produced from He-CO₂ (0.1 mole%) or He-N₂ (0.1 mole%) mixed gas, respectively, in a linear pinch tube, and the observed emission lines in λ500 to 1, 500A region were assigned and classified ; the lines due to the outer 2ₛ-shell electron excitation and those due to the valence 2p-electron excitation for OII-ions, NII-and OIII-ions and CII-, NIII-and OIV-ions, which are specified by the ground state configurations 2ₛ²2pᵐ with m＝3, 2 and 1, respectively, and the lines from the singly and doubly excited levels for CIII-, NIV-and OV-ions, which have the ground state configuration 2S². The relative intensity, the pressure dependence of intensity and the temporal behavior were observed on the spectral lines of both the outer 2ₛ and the valence 2p excitations. A possibility is suggested that the charge exchanges between He⁺ and impurity atoms or ions take place due to the rapid contraction of the plasma. For CIII- NIV-and OV-ions, it is seen that the lines from the doubly excited level 2p²(³P) to the metastable levels 2ₛ2p(³P⁰) show a remarkable afterglow after the pinch of the plasma

A Vision-Based Sensor for Noncontact Structural Displacement Measurement

Conventional displacement sensors have limitations in practical applications. This paper develops a vision sensor system for remote measurement of structural displacements. An advanced template matching algorithm, referred to as the upsampled cross correlation, is adopted and further developed into a software package for real-time displacement extraction from video images. By simply adjusting the upsampling factor, better subpixel resolution can be easily achieved to improve the measurement accuracy. The performance of the vision sensor is first evaluated through a laboratory shaking table test of a frame structure, in which the displacements at all the floors are measured by using one camera to track either high-contrast artificial targets or low-contrast natural targets on the structural surface such as bolts and nuts. Satisfactory agreements are observed between the displacements measured by the single camera and those measured by high-performance laser displacement sensors. Then field tests are carried out on a railway bridge and a pedestrian bridge, through which the accuracy of the vision sensor in both time and frequency domains is further confirmed in realistic field environments. Significant advantages of the noncontact vision sensor include its low cost, ease of operation, and flexibility to extract structural displacement at any point from a single measurement

Citizen Sensors for SHM: Use of Accelerometer Data from Smartphones

Ubiquitous smartphones have created a significant opportunity to form a low-cost wireless Citizen Sensor network and produce big data for monitoring structural integrity and safety under operational and extreme loads. Such data are particularly useful for rapid assessment of structural damage in a large urban setting after a major event such as an earthquake. This study explores the utilization of smartphone accelerometers for measuring structural vibration, from which structural health and post-event damage can be diagnosed. Widely available smartphones are tested under sinusoidal wave excitations with frequencies in the range relevant to civil engineering structures. Large-scale seismic shaking table tests, observing input ground motion and response of a structural model, are carried out to evaluate the accuracy of smartphone accelerometers under operational, white-noise and earthquake excitations of different intensity. Finally, the smartphone accelerometers are tested on a dynamically loaded bridge. The extensive experiments show satisfactory agreements between the reference and smartphone sensor measurements in both time and frequency domains, demonstrating the capability of the smartphone sensors to measure structural responses ranging from low-amplitude ambient vibration to high-amplitude seismic response. Encouraged by the results of this study, the authors are developing a citizen-engaging and data-analytics crowdsourcing platform towards a smartphone-based Citizen Sensor network for structural health monitoring and post-event damage assessment applications

Bimaximal Neutrino Mixing in a Zee-type Model with Badly Broken Flavor Symmetry

A Zee-type neutrino mass matrix model with a badly broken horizontal symmetry SU(3)_H is investigated. By putting a simple ansatz on the symmetry breaking effects of SU(3)_H for transition matrix elements, it is demonstrated that the model can give a nearly bimaximal neutrino mixing with the ratio $\Delta m^2_{solar}/\Delta m^2_{atm} \simeq \sqrt{2} m_e/m_{\mu}=6.7 \times 10^{-3}$, which are in excellent agreement with the observed data. In the near future, the lepton-number violating decay $Z\to \mu^\pm \tau^\mp$ will be observed.Comment: 10 pages, no figures, a comment adde

Vision-Based Displacement Sensor for Monitoring Dynamic Response Using Robust Object Search Algorithm

This paper develops a vision-based displacement measurement system for remote monitoring of vibration of large-size structures such as bridges and buildings. The system consists of one or multiple video cameras and a notebook computer. With a telescopic lens, the camera placed at a stationary point away from a structure captures images of an object on the structure. The structural displacement is computed in real time through processing the captured images. A robust object search algorithm developed in this paper enables accurate measurement of the displacement by tracking existing features on the structure without requiring a conventional target panel to be installed on the structure. A sub-pixel technique is also proposed to further reduce measurement errors cost-effectively. The efficacy of the vision system in remote measurement of dynamic displacements was demonstrated through a shaking table test and a field experiment on a long-span bridge