In this paper, a discretization of a three-dimensional fractional-order prey-predator model has been investigated with Holling type III functional response. All its fixed points are determined; also, their local stability is investigated. We extend the discretized system to an optimal control problem to get the optimal harvesting amount. For this, the discrete-time Pontryagin’s maximum principle is used. Finally, numerical simulation results are given to confirm the theoretical outputs as well as to solve the optimality problem.
Zinc oxide nanoparticles sample is prepared by the precipitation method. This method involves using zinc nitrate and urea in aqueous solution, then (AgNO3) Solution with different concentrations is added. The obtained precipitated compound is structurally characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). The average particle size of nanoparticles is around 28nm in pure, the average particle size reaches 26nm with adding AgNO3 (0.05g in100ml =0.002 M) (0.1g in100ml=0.0058M), AgNO3 (0.2g in 100ml=0.01M) was 25nm. The FTIR result shows the existence of -CO, -CO2, -OH, and -NO2- groups in sample and oxides (ZnO, Ag2O).and used an
... Show MoreHair is an excellent indicator for abnormal concentration of toxic elements , In this study a random samples from girls hair of 12 cm long were irradiated by a flux of neutrons (4x10^ n/ cm^.s) obtained from an Am-Be neutron source of 5-Ci activitity . The y-ray activity measurements were carried out by using a " 5x5 " well- type Nal (Tl) detector. The study indicates clearly that the maximum concentration of elements was at about 7 cm hair length.
In this paper, we proved that if R is a prime ring, U be a nonzero Lie ideal of R , d be a nonzero (?,?)-derivation of R. Then if Ua?Z(R) (or aU?Z(R)) for a?R, then either or U is commutative Also, we assumed that Uis a ring to prove that: (i) If Ua?Z(R) (or aU?Z(R)) for a?R, then either a=0 or U is commutative. (ii) If ad(U)=0 (or d(U)a=0) for a?R, then either a=0 or U is commutative. (iii) If d is a homomorphism on U such that ad(U) ?Z(R)(or d(U)a?Z(R), then a=0 or U is commutative.
A simple, rapid, accurate and sensitive spectrophotometric method has been developed for the determing carbamate pesticides in both pure and water samples. The method is appropriate for the determination of carbofuran in the presence of other ingredients that are usually available in dosage forms. The effect of organic solvents on the spectrophotometric properties of the azo dye and the structure of the resulting product have also been worked out and it is found to be 1:1 benzidine :carbofuran. The method can be successfully applied to determination of carbofuran in water samples. The method is based on diazotization of Benzidine (4, 4 – diamino biphenyl) with sodium nitrite and hydrochloric acid followed by coupling with carbofuran
... Show MoreBackground : surface area anatomy is a proportional point to the retention of complete denture, in past there was no quantitative method to evaluate the surface area, nowadays the size and shape of maxillary arch is measured by different electronically and mathematical devices. A study was therefore, undertaken to measure surface area of upper dental cast that was taken by different final impressions. Materials and methods: twenty patients were examined. All of them had a healthy palate with no singe of injury, trauma, or deformity. Casts were taken by three different final impressions; zinc oxide, additional silicon, and poly ether. And two different devices were used; the computerized one and the Aluminum foil measure. Age, se
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