Abstract: A new technique to quantify the differential mode
delay (DMD) in multimode fiber (MMF) is been presented. The
technique measures DMD based on angular launch and
measurements of the difference in modal delay using variable
apertures at the fiber face. The result of the angular spatial filtering
revealed less excitation of higher order modes when the laser beam is
filtered at higher angles. This result would indicate that DMD
profiles would experience a data pattern dependency.
Abstract: Based on Traub-s methods for solving nonlinear
equation f(x) = 0, we develop two families of third-order
methods for solving system of nonlinear equations F(x) = 0. The
families include well-known existing methods as special cases.
The stability is corroborated by numerical results. Comparison
with well-known methods shows that the present methods are
robust. These higher order methods may be very useful in the
numerical applications requiring high precision in their computations
because these methods yield a clear reduction in number of iterations.
Abstract: In this work, stationary hot-wire measurements are
carried out to investigate the characteristics of a round free jet in its
potential core region (0 ≤ x/d ≤ 10). Measurements are carried out on
an incompressible round jet for a range of Reynolds numbers from
4000 to 8000, calculated based on the jet exit mean velocity and the
nozzle diameter. The effect of flow velocity on the development
characteristics of the jet in the core region is analyzed. Timeaveraged
statistics, spectra of velocity and its higher order moments
are presented and explained.
Abstract: In this paper we developed the Improved Runge-Kutta Nystrom (IRKN) method for solving second order ordinary differential equations. The methods are two step in nature and require lower number of function evaluations per step compared with the existing Runge-Kutta Nystrom (RKN) methods. Therefore, the methods are computationally more efficient at achieving the higher order of local accuracy. Algebraic order conditions of the method are obtained and the third and fourth order method are derived with two and three stages respectively. The numerical results are given to illustrate the efficiency of the proposed method compared to the existing RKN methods.
Abstract: The objective of this study is to propose an observer design for nonlinear systems by using an augmented linear system derived by application of a formal linearization method. A given nonlinear differential equation is linearized by the formal linearization method which is based on Taylor expansion considering up to the higher order terms, and a measurement equation is transformed into an augmented linear one. To this augmented dimensional linear system, a linear estimation theory is applied and a nonlinear observer is derived. As an application of this method, an estimation problem of transient state of electric power systems is studied, and its numerical experiments indicate that this observer design shows remarkable performances for nonlinear systems.