Research ArticleOpen accessIn the abstractOn the Dynamics of a General Predator-Prey SystemM. M.A. El-Sheikh, S. A.A. El-Marouf, Z. M. AlaofyProblem statement: In this study a general two dimensional predator-prey model is considered. The dynamic and existence of equilibrium points are studied. Conclusion/Recommendations: Hopf bifurcation is discussed. The existence and uniqueness of limit cycles is proved. Special cases are considered to justify our results. …Journal of Mathematics and Statistics, Vol. 7, Issue 4 · 28 Oct 2011 · 7,322 accessesView PDFCite
Research ArticleOpen accessIn the abstractDevelopment of a Fully Coupled Approach for Evaluation of Wellbore Stability in Hydrocarbon ReservoirsVera RoccaProblem statement: When a well is drilled in a hydrocarbon reservoir, the original thermodynamic conditions are altered, the natural stresses are redistributed and a stress concentration occurs around the hole. The alteration of the original equilibrium can lead to wellbore damage, sometimes to its complete collapse. Loss of time associated with stability problems is estimated to account for 12-15% of … …American Journal of Environmental Sciences, Vol. 5, Issue 6 · 31 Dec 2009 · 7,559 accessesView PDFCite
Research ArticleOpen accessIn the abstractAdsorption Study of Several Hydrophobic Organic Contaminants on an Aquifer MaterialBarbara Ruffino, Mariachiara ZanettiProblem statement: Aim of the present research was to determine coefficient of partition KD between soil and groundwater for five hydrophobic organic pollutants (benzene, chlorobenzene, trichloroethylene-TCE, perchloroethylene-PCE and toluene) in an Italian aquifer material characterized by a low organic carbon content (fOC = 0.00262) by means of laboratory batch tests. Initial aqueous concentrations (quite different among the five compounds) were … …American Journal of Environmental Sciences, Vol. 5, Issue 4 · 31 Aug 2009 · 7,366 accessesView PDFCite
Research ArticleOpen accessIn the abstractGlobal Behavior of a Higher Order Difference EquationAlaa E. Hamza, R. Khalaf-AllahIn this work we study the asymptotic stability of the nonnegative equilibrium points of the difference equation. We discuss the conditions under which there exist prime period two solutions and semicycles. Finally we investigate the oscillation and the existence of unbounded solutions. …Journal of Mathematics and Statistics, Vol. 3, Issue 1 · 31 Mar 2007 · 7,054 accessesView PDFCite
Research ArticleOpen accessIn the abstractEpidemiological Models Applied to Viruses in Computer NetworksJos R.S. Piqueira, Betyna F. Navarro, Luiz H.A. MonteiroTo investigate the use of classical epidemiological models for studying computer virus propagation we described analogies between computer and population disease propagation using SIR (Susceptible-Infected-Removed) epidemiological models. By modifying these models with the introduction of anti-viral individuals we analyzed the stability of the disease free equilibrium points. Consequently, the basal virus reproduction rate gives some theoretical hints about how to … …Journal of Computer Science, Vol. 1, Issue 1 · 31 Mar 2005 · 7,574 accessesView PDFCite
Research ArticleOpen accessAll words, across the recordBIFURCATION ANALYSIS OF EQUILIBRIUM POINT IN TWO NODE POWER SYSTEMHalima Aloui, Faouzi Bacha, Moncef GasmiThis study presents a study of bifurcation in a dynamic power system model. It becomes one of the major precautions for electricity suppliers and these systems must maintain a steady state in the neighborhood of the operating points. We study in this study the dynamic stability of two node power systems theory and the stability of limit cycles emerging from … …American Journal of Applied Sciences, Vol. 11, Issue 4 · 29 Jan 2014 · 7,055 accessesView PDFCite