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Full-Text Articles in Physical Sciences and Mathematics

A Boundedness And Stability Results For A Kind Of Third Order Delay Differential Equations, Moussadek Remili, Djamila Beldjerd Dec 2015

A Boundedness And Stability Results For A Kind Of Third Order Delay Differential Equations, Moussadek Remili, Djamila Beldjerd

Applications and Applied Mathematics: An International Journal (AAM)

The objective of this study was to get some sufficient conditions which guarantee the asymptotic stability and uniform boundedness of the null solution of some differential equations of third order with the variable delay. The most efficient tool for the study of the stability and boundedness of solutions of a given nonlinear differential equation is provided by Lyapunov theory. However the construction of such functions which are positive definite with corresponding negative definite derivatives is in general a difficult task, especially for higher-order differential equations with delay. Such functions and their time derivatives along the system under consideration must satisfy …


A Stage-Structured Two Species Competition Mathematical Model Under The Effect Of Disease, Manju Agarwal, Vinay Verma Jun 2015

A Stage-Structured Two Species Competition Mathematical Model Under The Effect Of Disease, Manju Agarwal, Vinay Verma

Applications and Applied Mathematics: An International Journal (AAM)

In this paper we study the dynamics of two competing species model; one of this competing species is stage structured and the disease spreads only in the other competing specie. In order to keep the model simple, we present it under the strong assumption that the disease can not cross the species barrier. Dynamical behaviors such as positivity, boundedness, stability, bifurcation and persistence of the model are studied analytically using the theory of differential equations. Computer simulations are carried out to substantiate the analytical findings. It is noted that c the loss rate of the population, T the maturation time …


Analysis And Simulation Of Semiconductor Laser Dynamics With Optoelectronic Delay Feedback, Varghese Bejoy, Sivasankaran Rajesh, Vadakkedath Madhom Nandakumaran Jan 2015

Analysis And Simulation Of Semiconductor Laser Dynamics With Optoelectronic Delay Feedback, Varghese Bejoy, Sivasankaran Rajesh, Vadakkedath Madhom Nandakumaran

Turkish Journal of Physics

In this work we investigate semiconductor laser dynamics with optoelectronic delay feedback, both analytically and numerically. Stability criteria are derived from the delay differential equations of the system. Stability curves are obtained in the feedback strength-delay parameter space. We show that delay has a role in determining the stability only for a range of feedback strength and this range can vary depending on other parameters. Effects of bias current and nonlinear gain reduction on the stability curves are shown in the analysis and numerically verified.


Stability Of Compact Ricci Solitons Under Ricci Flow, Mina Vaghef, Asadollah Razavi Jan 2015

Stability Of Compact Ricci Solitons Under Ricci Flow, Mina Vaghef, Asadollah Razavi

Turkish Journal of Mathematics

In this paper we establish stability results for Ricci solitons under the Ricci flow, i.e. small perturbations of the Ricci soliton result in small variations in the solution under Ricci flow.


Stability Of Perturbed Dynamic System On Time Scales With Initial Time Difference, Coşkun Yakar, Bülent Oğur Jan 2015

Stability Of Perturbed Dynamic System On Time Scales With Initial Time Difference, Coşkun Yakar, Bülent Oğur

Turkish Journal of Mathematics

The behavior of solutions of a perturbed dynamic system with respect to an original unperturbed dynamic system, which have initial time difference, are investigated on arbitrary time scales. Notions of stability, asymptotic stability, and instability with initial time difference are introduced. Sufficient conditions of stability properties are given with the help of Lyapunov-like functions.


Preparation And Physicochemical Characterizations Of Solid Lipid Nanoparticles Containing Dotap$^®$ For Dna Delivery, Gülay Büyükköroğlu, Emi̇ne Yasemi̇n Yazan, Ayşe Fi̇li̇z Öner Jan 2015

Preparation And Physicochemical Characterizations Of Solid Lipid Nanoparticles Containing Dotap$^®$ For Dna Delivery, Gülay Büyükköroğlu, Emi̇ne Yasemi̇n Yazan, Ayşe Fi̇li̇z Öner

Turkish Journal of Chemistry

The aim of this study was to prepare and evaluate stable cationic solid lipid nanoparticles (SLNs) as colloidal carriers for gene therapy. SLNs were mainly composed of three different biocompatible and biodegradable matrix lipids called tripalmitin, glyceryl dibehenate, and triglyceride, all containing the cationic lipid $N$-(1-(2,3-dioleoyloxy)propyl)-$N,N,N$-trimethylammonium (DOTAP$^®$). Each of these SLNs were divided into three parts and characterized by applying different processes: Part I was autoclaved (121 $^{\circ}$C, 15 min), Part II was lyophilized (5 mbar, --50 $^{\circ}$C), and Part III was kept in its intact form. These parts were stored at 4 $^{\circ}$C, 25 $^{\circ}$C (room temp.), and 40 …