Sürdürülebilir Kalkınma Amaçları
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- MakaleYalnız künye2019GLOBAL STABILITY IN A PATHOGEN-SPECIFIC CD8 IMMUNE RESPONSE PREDICTION MODEL
Anaç, Halil; Merdan, Mehmet; Beki̇Ryazici, Zafer
In this study, a system of ordinary differential equations used for modeling pathogen-specific CD8 cell immune response is studied. The positivity and the limitation of the model solutions are proven. The equilibrium points in the cases with the presence and the absence of the pathogen are determined and their stabilities are investigated. Furthermore, the essential reproduction number is obtained for the system. The conditions of the reproduction number for the stability of the equilibrium are shown and numerical examples are given for supporting the analytical results.
- MakaleAçık Erişim2014Assessment of kinetics, thermodynamics, and equilibrium parameters of Cu(II) adsorption onto Rosa canina seeds
Serencam, Huseyin; Ozdes, Duygu; Duran, Celal; Senturk, Hasan Basri
Rosa canina seeds (RCS) is considered as a low-cost and promising adsorbent in removal of metal ions; hence, in the present study, we aimed to test the adsorptive removal of Cu(II) ions from aqueous solutions by utilizing RCS in a batch process. After characterization of RCS by using several techniques, the effects of various experimental parameters such as initial pH of aqueous solution, contact time, initial Cu(II) concentration, RCS concentration, temperature, and electrolyte concentration were studied upon the adsorption process. The desorption conditions of Cu(II) ions from the loaded RCS were also evaluated. Maximum Cu(II) adsorption was found to occur at pH 6.0 and the equilibrium was established after 60 min of contact time. The adsorption isotherms were described by means of Langmuir, Freundlich, Temkin, and Dubinin Radushkevich models. The adsorption kinetics were analyzed using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models and the adsorption data were well described by the pseudo-second-order model. Thermodynamic parameters such as the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes were also evaluated and it has been found that the adsorption process was feasible, spontaneous, and endothermic in the temperature range of 278-313 K.
- MakaleYalnız künye2014Assessment of kinetics, thermodynamics and equilibrium parameters of Cr(VI) biosorption onto Pinus brutia Ten
Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Kucuk, Murat; Soylak, Mustafa
The aim of the present study was to investigate the sorption potential of pine bark (Pinus brutia Ten.) for removal of Cr(VI) ions from aqueous solutions. The biosorption characteristics of Cr(VI) ions onto bark biomass were examined with respect to the changes in initial pH of the solution, contact time, initial Cr(VI) and bark concentration, bark particle size, temperature, etc. The biosorption isotherms were described by means of Langmuir and Freundlich models and the biosorption kinetics were analysed using pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The thermodynamic parameters proved that the process was feasible, spontaneous and endothermic in nature.