An experimental study on pulse detonation engine (PDE) is conducted using hydrogen/air mixtures. Several key issues for PDE development, including valve operation, injection, mixing, filling, cycle repetition, ignition timing, DDT distance and propagation of detonation/quasi-detonation, are investigated. The fuel and oxidizer are injected into PDE from opposite sidewall directions to be well mi...

The suprachiasmatic nuclei of the hypothalamus contain the major circadian pacemaker in mammals, driving circadian rhythms in behavioral and physiological functions. This circadian pacemaker's responsiveness to light allows synchronization to the light-dark cycle. Phase shifting by light often involves several transient cycles in which the behavioral activity rhythm gradually shifts to its stea...

in recent years, there has been greater attempt to find numerical solutions of differential equations using wavelet's methods. the following method is based on vector forms of haar-wavelet functions. in this paper, we will introduce one dimensional haar-wavelet functions and the haar-wavelet operational matrices of the fractional order integration. also the haar-wavelet operational matrice...

In this paper, we perform a theoretical study of processes that demonstrates additional time delay obtained by remodeling Brillouin gain spectrum, and we also study the main influence factors on pulse time delay and broadening, as well as analyze the ways which increases the delay, and further suppresses pulse broadening. The results show that by remodeling Brillouin gain spectrum, one obtains ...

We describe a methodology to maximize slow-light pulse delay subject to a constraint on the allowable pulse distortion. We show that optimizing over a larger number of physical variables can increase the distortion-constrained delay. We demonstrate these concepts by comparing the optimum slow-light pulse delay achievable using a single Lorentzian gain line with that achievable using a pair of c...

A coupled method of Laplace transform and Legendre wavelets is presented to obtain exact solutions of Lane-Emden-type equations. By employing properties of Laplace transform, a new operator is first introduced and then its Legendre wavelets operational matrix is derived to convert the Lane-Emden equations into a system of algebraic equations. Block pulse functions are used to calculate the Lege...

A numerical method for solving nonlinear mixed Hammerstein integral equations is presented in this paper. The method is based upon hybrid of rationalized Haar functions approximations. The properties of hybrid functions which are the combinations of block-pulse functions and rationalized Haar functions are first presented. The Newton-Cotes nodes and Newton-Cotes integration method are then util...

A numerical method based on modified block pulse functions is proposed for solving the mixed linear Volterra-Fredholm integral equations. We obtain an integration operational matrix of interval [0,T). and their integration, equations can be reduced to a system algebraic The rate convergence O(h) error analysis are discussed. Some examples provided show that have good degree accuracy.