This study has three parts, the first one is the synthesis of a novel Schiff bases by the condensation of guanine or 9-[{2-hydroxyethoxy}methyl]-9H-guanine with variety aldehydes to yield four different bases as follows: (E)-2-((4-nitrobenzylidene)amino)-1,9-dihydro-6H-purin-6-one (S1), (E)-2-((4-methoxybenzylidene)amino)-1,9-dihydro-6H-purin-6-one (S2), (E)-2-((2-hydroxybenzylidene) amino)-9-((2-hydroxy ethoxy)methyl)-1,9-dihydro-6H-purin-6-one (S3), and (E)-2-(((9-((2-hydroxy ethoxy)methyl)-6-oxo-6,9-dihydro-1H-purin-2-yl)imino)methyl)benzoic acid (S4). Then, spectroscopic analyses such as Elemental Analysis, UV/VIS, Mass spectra, FTIR, 1H,13C-NMR were made to recognize these bases. In the second part, the ability of synthesized bases to undergo a charge transfer reaction was examined in an ethanolic solution at 28℃ with Iodine (I2) and 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) acceptors. The nonbonding interactions were studied using Benesi–Hildebrand method to estimate the stability parameters for all formed charge transfer complexes. The results of CT-energies and Gibbs free energies (ΔG˚) confirmed the stability of these complexes, and all complexes follow the Benesi–Hildebrand equation. The results showed that the DDQ-complexes have an affinity constant ranging from (916.6–24,400) mol−1.L higher than the affinity constant of I2-complexes which ranges from (428.5–7000) mol−1.L. Moreover, the KCT of S2 > S1 and KCT of S4 > S3 were as follows [1222.2 for S1-I2, 4333.3 for S1-DDQ, 2812.5 for S2-I2, 4800 for S2-DDQ] and [3809.5 for S3-I2, 12,200 for S3-DDQ, 7000 for S4-I2, 24,400 for S4-DDQ] due to the specific properties of each compound. The direct energy gap (Egdir) of each complex was also obtained by applying Tauc's method. Iodine complexes with S1, S2, S3, S4, as well as S1-DDQ displayed energy gaps equal to (5.14, 5.11, 4.61, 4.51, and 3.90) eV, respectively, and are likely to act as insulators. In contrast, the DDQ complexes of (S2/S3/S4) bases exhibited Egdir values at (2.85–2.24) electron volts which makes them suitable for semiconductor material usage. Finally, the third part of this work included a theoretical study using DFT/B3LYP/3-21G method to illustrate and prove the experimental findings, which were consistent with the theoretical results.
The dye–semiconductor interface between N749 sensitized and zinc semiconductor (ZnSe) has been investigated and studied according to quantum transition theory with focusing on the electron transfer processes from the N749 sensitized (donor) to the ZnSe semiconductor (acceptor). The electron transfer rate constant and the orientation energy were studied and evaluated depended on the polarity of solvents according to refractive index and dielectric constant coefficient of solvents and ZnSe semiconductor. Attention focusing on the influence of orientation energies on the behavior of electron transfer rate constant. Differentdata of rate constant was discussion with orientation energy and effective driving energy for N749-ZnSe system.
... Show MoreA numerical method is developed for calculation of the wake geometry and aerodynamic forces on two-dimensional airfoil under going an arbitrary unsteady motion in an inviscid incompressible flow (panel method). The method is applied to sudden change in airfoil incidence angle and airfoil oscillations at high reduced frequency. The effect of non-linear wake on the unsteady aerodynamic properties and oscillatory amplitude on wake rollup and aerodynamic forces has been studied. The results of the present method shows good accuracy as compared with flat plate and for unsteady motion with heaving and pitching oscillation the present method also shows good trend with the experimental results taken from published data. The method shows good result
... Show MoreThis work represents implementation and investigation of optical coherent communication system between two computers. A single mode optical fiber is selected as transmission medium. The data are sent via the RS-232 standard interface with a bit rate of 9.6 kbps from personal computer (PC1) by line receive to convert the data from electrical levels (-12/+12 V) into TTL level (0/5 V). The modulation of this data was accomplished by internal modulation using laser diode type (HFCT-5208M) 1310 nm wavelength. The optical D-coupler was used to combine the optical signal that come from laser source with optical signal of laser local oscillator (OTS-304XI) at 1310/1550 nm wavelength to obtain coherent (homodyne and heterodyne) detection respective
... Show MoreA theoretical and experimental investigation was carried out to study the behavior of a two-phase closed thermosyphon loop (TPCTL) during steady-state operation using different working fluids. Three working fluids were investigated, i.e., distilled water, methanol, and ethanol. The TPCTL was constructed from an evaporator, condenser, and two pipelines (riser and downcomer). The driving force is the difference in pressure between the evaporator and condenser sections and the fluid returns to the heating section by gravity. In this study, the significant parameters used in the experiments were filling ratios (FR%) of 50%, 75%, and 100% and heat-input range at the evaporator section of 215-860.2 W. When the loop reached to
... Show MoreTraditional tree management is laborious and costly, thus this work aimed to study the performance of two different types of frond cutting saws (reciprocating saw and vibrating saw) and examine the two saws on five date palm varieties. Four parameters were examined, including cutting time for a single frond, the power needed for cutting a single frond, frond cutting productivity expressed as tree/h, and vibration conveyed to the worker’s hand. A field experiment was designed according to the nested randomized complete block design, including five date palm varieties as the main plot and the type of saw as a sub-plot. Means were compared using the least significant differences (LSD 0
The present work evaluated the differences in mechanical properties of two athletic prosthetic feet samples when subjected to impact while running. Two feet samples designated as design A and B were manufactured using layers of different orientations of woven glass fiber reinforced with unsaturated polyester resin as bonding epoxy. The samples’ layers were fabricated with hand lay-up method. A theoretical study was carried out to calculate the mechanical properties of the composite material used in feet manufacturing, then experimental load-deflection test was applied at 0 degree position and 25 degree dorsiflexion feet position and impact test were applied for both feet designs to observe the behavior
... Show MoreAutorías: Muhammad Hamza Shihab, Nuha Mohsin Dhahi. Localización: Revista iberoamericana de psicología del ejercicio y el deporte. Nº. 4, 2022. Artículo de Revista en Dialnet.
Nonlinear time series analysis is one of the most complex problems ; especially the nonlinear autoregressive with exogenous variable (NARX) .Then ; the problem of model identification and the correct orders determination considered the most important problem in the analysis of time series . In this paper , we proposed splines estimation method for model identification , then we used three criterions for the correct orders determination. Where ; proposed method used to estimate the additive splines for model identification , And the rank determination depends on the additive property to avoid the problem of curse dimensionally . The proposed method is one of the nonparametric methods , and the simulation results give a
... Show More