Basrah Journal of Science

This paper is defined and studied a new r-th powers of rational Bernstein polynomials. The convergence theorem, the recurrence relation for the m-th order moment, and the Voronovskaya-type asymptotic formula for these polynomials in ordinary approximation are given. Also, a numerical example for these polynomials is applied to approximate the test function sin⁡10x∈C[0,1]. The results obtained from this example are shown that these polynomials are given better than the corresponding numerical results for the classical Bernstein polynomials and the square rational Bernstein polynomials. The comparison is done by plot the graphs of the function and its approximations as well as the evaluation of the average absolute errors for these approximations.

In this paper, we consider the repeated measurement model. We estimate the parameters of the model by using the maximum likelihood method and compared these estimators with the penalized likelihood estimators by using mean square error. We also determine the corresponding moments of each estimators. Finally, we find bias equations and variance for each estimator.

The study of a nonlinear mathematical fractional SIR (Susceptible - Infected - Recovered) epidemiological model related to the delay in state and control variables in terms of time is the focus of this paper. The existence of a bounded solution for the fractional SIR epidemic model has been demonstrated, and it is unique. A new set of infection-free equilibrium points has been discovered, and their local stability has been investigated. In addition, using the next-generation matrix method, the basic reproductive number was calculated.

In this paper, the bifurcation solutions of the boundary condition problem has been studied by using the local method from Lyapunov-Schmidt. We reduce the bifurcation equation and make it in the form of Operator equation. In addition, the finite dimensional reduction theorem for the bifurcation equation is given by the nonlinear system of fourth order equations. We investigate the analysis system of the bifurcation equation; we also find the Discriminant set of corresponding to the nonlinear differential equation by using (Maple 201‪6) program. The classification of the equilibrium points of the Dynamical System are discussed. And the phase portrait of boundary condition problem is found in three dimensional.‬‬‬‬‬‬‬‬‬‬‬‬‬‬

The electrical performance of bottom-gate/top source-drain contact for p-channel organic field-effect transistors (OFETs) using poly(3-hexylthiophene) (P3HT) as an active semiconductor layer with two different gate dielectric materials, Polyvinylpyrrolidone (PVP) and Hafnium oxide (HfO2), is investigated in this work. The output and transfer characteristics were studied for HfO2, PVP and HfO2/PVP as organic gate insulator layer. Both characteristics show a high drain current at the gate dielectric HfO2/PVP equal to -0.0031A and -0.0015A for output and transfer characteristics respectively, this can be attributed to the increasing of the dielectric capacitance. Transcondactance characteristics also studied for the three organic materials and show the HfO2/PVP gate dielectric have higher value from the single layers which indicate the effect of dielectric capacitance, gm=-0.5517x10-4A/V, -0.9931x10-5A/V, and -0.6511 x10-4A/V respectively.

Ag nanoparticles (Ag NPs) were prepared via simple chemical method at 200 oC for 2 hours using chitosan extract and sliver (iii) nitrate (Ag2NO3) salt. The chitosan extract acts as a reducing, stabling and anti-caking agent to transfer Ag2NO3 salt to Ag NPs in short period of time. Some physical properties of prepared Ag NPs are investigated using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), optical absorption which used to characterize the structural, morphology, and optical properties of prepared samples. The crystallite size of Ag NPs that prepared using chitosan extract was ranged from (20.8 to 64.4 ) nm with a cube shape . UV-Vis absorption spectrum of prepared Ag NPs showed that the energy gap is 3.6 eV. FESEM images confirmed that particles size of prepared Ag NPs wan ranged from 52 nm to 91 nm with spherical shape. Antibacterial activity of prepared Ag NPs was test against two type of bacteria, Gram-positive (Staphylococcus) and Gram-negative (Escherichia coils).

In this work, polyvinylpyrrolidone (PVP), Multi-walled carbon nanotubes (MWCNTs) nanocomposite was prepared and hybrid with Graphene (Gr) by casting method. The morphological and optical properties were investigated. Fourier Transformer-Infrared (FT-IR) indicates the presence of primary distinctive peaks belonging to vibration groups that describe the prepared samples. Scanning Electron Microscopy (SEM) images showed a uniform dispersion of graphene within the PVP-MWCNT nanocomposite. The results of the optical study show decrease in the energy gap with increasing MWCNT and graphene concentration. The absorption coefficient spectra indicate the presence of two absorption peaks at 282 and 287 nm attributed to the π-π* electronic transition which is found in MWCNT and Gr. The energy gap (Eg) has been obtained from the indirect allowed transition. It was found that, Eg decrease with the addition of MWCNTs and Gr content.

Lead is a naturally occurring toxic metal found in the earth's crust. Its widespread use has resulted in extensive environmental contamination, human exposure and significant public health problems in many parts of the world. In this study we report the preparation of three esters impregnated with magnetic nanoparticles Fe3O4, esters prepared from 2,2-bis(hydroxyl methyl)propane-1,3-diol with 4-hydroxy benzoic acid (I), nicotinic acid (niacin) (II) and stearic acid (III). The synthesis absorbents (I@Fe3O4, II@Fe3O4 and III@Fe3O4) proved to be effective for the removal of lead ions from aqueous solution at near-neutral pH, the adsorption behavior was matching with Langmuir model for I@Fe3O4 and II@Fe3O4 and in keeping with Freundlich model for III@Fe3O4 with qmax values of 862.068 mg/g, 1149.425 mg/g and 261.096 mg/g respectively. The adsorption of Pb(II) follows pseudo-first-order kinetics for three adsorbents.

Cobalt nanoparticles were synthesized by reduction-oxidation method. The reaction was done using cobalt salts as the source of metal and eucalyptus leaf as a reducing material and trisodium citrate used as capping agent. The creation of the cobalt nanoparticles was monitored using UV-Vis spectroscopy. The UV-Vis spectroscopy shown the formation of cobalt nanoparticles by exhibing the typical surface plasmon absorption maximum at 570 nm. Fourier transform infrared spectra (FTIR) used for characterization of eucalyptus leaf some functional groups that related with cobalt nanoparticles was showed. Field emission scanning electron microscope (FESEM) was monitored to characterize the morphology and the size of cobalt nanoparticles, images from FESEM indicate that the synthesis of cobalt nanoparticles in the range (15-85 nm). Dynamic light scattering (DLS), by zeta sizer analysis showed the distribution of nanoparticles in nano range; moreover, zeta potential analysis clarified the distribution of cobalt nanoparticles in a negative value (-20.3mV), which indicate presence of stable and positive cobalt ions. The production of cobalt nanoparticles were applied for removal of heavy metals from polluted water and flame atomic absorption spectroscopy (FAAS) was used for determination of polluted metals before and after the addition of nano cobalt.

The wheat plant, Triticum aestivum L., is one of top cereal crops in the world, followed by the rice and corn crops; and it is one of the most important food crops for more than a third of the world's population. in recent times, several studies focused on finding ways to increase and encourage growth and production of wheat, and among these methods is the use of nanomaterials. The present study has been conducted to evaluate the nanomaterials titanium dioxide (TiO2) and zinc oxide (ZnO) efficacy in the growth promoting of three cultivars of wheat plant (Ibaa 99, Abu Ghraib and Bhooth 22). Laboratory experiments proved the non-toxicity of TiO2 and ZnO on the germination of wheat seeds. All treatments were 100% germinated, whereas the results showed the superiority of TiO2 in stimulating all examined parameters. The examined parameters, whether in Petri plates or pots, including the length of the radicle and hypocotyl, compared to a control treatment. The results of the pots experiment showed that the concentration of 100 ppm significantly exceeded the rest of the tested concentrations (0, 25 and 50 ppm), and the Abu Ghraib cultivar was the most responsive to nanomaterials. It is worth noting that the nanomaterials TiO2 and ZnO at a concentration of 100 ppm led to an increase in some biochemical indicators, including photosynthesis pigments, carbohydrate content and proline, compared to the control treatment in the cultivar Abu Ghraib.The current study recommends that TiO2 and ZnO should be used in the treatment of wheat plants, with more studies being conducted on other economic plants.