We calculate the spectrum of collective excitations of the XY spiral state prepared adiabatically or suddenly from a uniform ferromagnetic F=1 condensate. For spiral wave vectors past a critical value, spin wave excitation energies become imaginary indicating a dynamical instability. We construct phase diagrams as functions of spiral wave vector and quadratic Zeeman energy.

In high-resolution resonant inelastic x-ray scattering at the Ti L edge of the charge-density-wave system 1T-TiSe(2), we observe sharp low energy loss peaks from electron-hole pair excitations developing at low temperature. These excitations are strongly dispersing as a function of the transferred momentum of light. We show that the unoccupied bands close to the Fermi level can effectively be p...

The weather forecast by satellite data is a good guideline for assessment of voyage planning route in order to have safe and economic voyage for shipping. ISO15016, "Guidelines for the assessment of speed and performance by analysis of speed trial data", has been developed by the working group ISO/TC 8/SC 9/WG 2. This paper presents the effects of wave speed & direction, wind speed and directio...

To control structures against wind and earthquake excitations, Adaptive Neuro Fuzzy Inference Systems and Neural Networks are combined in this study. The control scheme consists of an ANFIS inverse model of the structure to assess the control force. Considering existing ANFIS controllers, which require a second controller to generate training data, the authors’ approach does not need anot...

advantages and disadvantages of using “stokes parameters” in exploration of inertia-gravity wave properties are discussed in this paper. the survey is carried out on an inertia-gravity wave event (igws in what follows) that occurred over iran from 7 to 9 february 2012. applying this technique for investigation of atmospheric igws was recommended by vincent and fritts (1987) and then developed b...

The rapid Arctic summer sea ice reduction in the last decade has lead to debates in the maritime industries on the possibility of an increase in cargo transportation in the region. Average sailing times on the North Sea Route along the Siberian Coast have fallen from 20 days in the 1990s to 11 days in 2012– 2013, attributed to easing sea ice conditions along the Siberian coast. However, the eco...

A model of surface waves generated on deep water by strong winds is proposed. A two-layer approximation is adopted, in which a shallow turbulent layer overlies the lower, infinitely deep layer. The dynamics of the upper layer, which is directly exposed to the wind, are nonlinear and coupled to the linear dynamics in the deep fluid. The authors demonstrate that in such a system there exist stead...

Wind is one of the main forces affecting the rate of forest fire spread. It may either increase or decrease the energy transferred toward the unburned areas. The present study is devoted to understanding the effect of wind on the propagation of forest fires. To model the propagation of forest fires a semiphysical approach is used. By this approach forest fire is considered as an adiabatic combu...