Aq Psc – Analysis of New Light Curves

New BV light curves of the A-type W UMa star AQ Psc (P = 0.476d) have been observed and are described. A few times of minimum light are obtained and the ephemeris is improved. The light curves are analyzed for the binary parameters with a light curve synthesis method. Combining the results with Lu and Rucinski’s spectroscopic mass ratio we determined the masses and radii of the components: M ₁ = 1.69M _⊙, M ₂ = 0.38M _⊙, R ₁ = 1.77R _⊙, and R ₂ = 0.89R _⊙.     

Fourier analysis of the light curves of eclipsing variables

The aim of the present paper has been to construct analytic expressions for incomplete Fourier transforms underlying Kitamura's method for an analysis of the light curves of eclipsing binary systems (Kitamura, 1965).The expansions established for Kitamura's coefficientsc _n ands _n have been used as a basis for checking numerical accuracy of these coefficients tabulated by Kitamura in 1967; and the outcome bespeaks a high quality of his tables constructed by numerical quadratures.     

Negative detection of the four-hour periodicity of the central star of M1-2 (VV8)

Four-hour (4.0002 hr) binary periodicity of the emission-line object M1-2 (=VV8), claimed by Drummond (1980), is examined on the basis of photometric and spectroscopic observations. However, neither positive variation of the light nor that of the radial velocity associated with that period has been found.     

Geometry of stress function surfaces for an asymmetric continuum

A two-dimensional stress field of dislocation or fault is geometrically studied for an asymmetric continuum. For geometric surfaces of the stress and couple-stress functions, the mean and Gaussian curvatures are derived. The mean curvature of couple-stress function surface is connected with the asymmetric of stress tensor. Moreover, the Gaussian curvature of stress function surface is characterized by both the stress and couple-stress. On the other hand, the mean curvature of stress function surface is not affected by the asymmetry of stress. Based on these geometric expressions, the Coulomb’s failure criterion and the friction coefficient are expressed by the curvatures of couple-stress function surface. Moreover, geometric structures of stress and couple stress function surfaces are shown for edge and wedge dislocations as faults. The curvatures of these surfaces show that the effect of couple-stress is constrained around the dislocations only.     

Differential geometric approach to the stress aspect of a fault: Airy stress function surface and curvatures

We considered the two-dimensional stress aspect of a fault from the viewpoint of differential geometry. For this analysis, we concentrated on the curvatures of the Airy stress function surface. We found the following: (i) Because the principal stresses are the principal curvatures of the stress function surface, the first and the second invariant quantities in the elasticity correspond to invariant quantities in differential geometry; specifically, the mean and Gaussian curvatures, respectively; (ii) Coulomb’s failure criterion shows that the coefficient of friction is the physical expression of the geometric energy of the stress function surface; (iii) The differential geometric expression of the Goursat formula shows that the fault (dislocation) type (strike-slip or dip-slip) corresponds to the stress function surface type (elliptic or hyperbolic). Finally, we discuss the need to use non-biharmonic stress tensor theory to describe the stress aspect of multi-faults or an earthquake source zone.     

A photometric and spectroscopic study of the short-period eclipsing binary BV Eridani

UBV observations of the short-period eclipsing binary BV Eri are reported and analyzed. The radial velocity curve is given. The system shows a light curve distortion, making an analysis difficult. The secondary fills its critical Roche lobe. The system seems to be in an interesting evolutionary.     

A quantum particle motion and thermodynamics in faults-defects field: Path integral formulation based on extended deformation gradient tensor

We consider the effect of the faults-defects (FD) field on the following quantum phenomena: (i) the motion of a particle expressed by the Green function; (ii) thermodynamic phenomena expressed by the partition function. We use the path integral formulation based on the extended deformation gradient (EDG) tensor. This formulation connects the Green function of (i) with the partition function of (ii) to describe the thermodynamics in terms of a quantum particle motion. We obtain the following results: (a) The Lagrangian in the Green function includes the new potential consisting of stress functions that shift the path of the free particle from the shortest distance; (b) The solution of the partition function in one-dimensional space makes it possible to deduce the thermodynamic relations in the FD field. Such results could not be obtained by taking the traditional mechanical and quantum approaches, so the path integral formulation based on the EDG tensor is a useful tool.     

A photometric study of the short-period eclipsing binary BW Eridani

UBV observations of the short-period eclipsing binary BW Eri are reported and analyzed. The photometric parameters are determined. BW Eri is a detached or semidetached system.     

Pyroclastic flows in Japan

Bulletin of Volcanology -     

Long-traveling landslides in deep snow conditions induced by the 2011 Nagano Prefecture earthquake,Japan

Earthquakes in mountainous areas may produce many landslides that involve abundant snow, but few observations have been made of these hazardous phenomena. The 12 March 2011 north Nagano Prefecture earthquake (M_JMA 6.7) occurred in a mountainous part of Japan that typically has an annual snow cover of more than 2 m, and it induced many snowy landslides. Some of these traveled relatively long distances. We examined the snowy Tatsunokuchi landslide to reconstruct the landsliding processes over deep snow. We infer that the Tatsunokuchi landslide occurred by collapse of a rock debris mass of 5?×?10⁴ m³ that plunged into the abundant snow, forming a mixture of snow and rock debris, which then traveled on top of the snow. Later, the displaced mass included a large amount of snow which was pushed forward at the front and to the sides. The velocity of the landslide was estimated to be approximately 14 m/s. It appears that the displaced mass, having only a small proportion of rock debris, had a low enough density to travel easily on top of the snow. Our observations suggest that there was much liquid water at the base of the displaced mass shortly after the event. Our results suggest that landslides may damage wider areas than expected if they travel over deep snow.