In this work, solid random gain media were fabricated from laser dye solutions containing nanoparticles as scattering centers. Two different rhodamine dyes (123 and 6G) were used to host the highly-pure titanium dioxide nanoparticles to form the random gain media. The spectroscopic characteristics (mainly fluorescence) of these media were determined and studied. These random gain media showed laser emission in the visible region of electromagnetic spectrum. Fluorescence characteristics can be controlled to few nanometers by adjusting the characteristics of the host and nanoparticles as well as the preparation conditions of the samples. Emission of narrow linewidth (3nm) and high intensity in the visible region (533-537nm) was obtained.
Corrosion inhibiting admixtures are unique among other methods to protect reinforced concrete from corrosion damage. In this study, the effect of furfural on the fresh and hardened properties of concrete mixes of 35 and 45 MPa compressive strengths as well as the corrosion inhibition of furfural was evaluated. Furfural was added at different dosages (1, 2 and 3% by weight of cement) with and without superplasticizer (HRWR). Different electrochemical measurements were performed (Half-cell potential, Tafel plot and linear polarization resistance). Electrochemical measurements confirmed that furfural dramatically reduces the rate of corrosion; the inhibition efficiencies were 62.7 and 63.8 % due to 3% furfural addition to 35 and 45MPa-concr
... Show MoreIR, MIR, UV – Visible spectra have been studied for Cobalt chloride molecule (CoCl2. 6H2O) compound, In wide range spectra (40000 – 410) cm-1 specially MIR range. Assignment were achieved for the fundamental vibrational bands of (CoCl2 . 6H2O ) to symmetry stretching ?1 (?^+) Anti – symmetry stretching ?3(?^+), these bands are non-degenerate , and the bending band is ?2(?) is doubly degenerate thought they have activity in IR and Raman , which explain the weakness in symmetry of this molecule, the fundamental bands for the molecule are centered at the following wave numbers (615, 685, 795, 1115, 1340, 1375, 1616.35, 2091, 2386, 2410, 3364) cm-1 which are corresponding to wave lengths (16260, 14598, 12578, 8968, 7462, 7272, 6186,
... Show MoreHeart disease identification is one of the most challenging task that requires highly experienced cardiologists. However, in developing nations such as Ethiopia, there are a few cardiologists and heart disease detection is more challenging. As an alternative solution to cardiologist, this study proposed a more effective model for heart disease detection by employing random forest and sequential feature selection (SFS). SFS is an effective approach to improve the performance of random forest model on heart disease detection. SFS removes unrelated features in heart disease dataset that tends to mislead random forest model on heart disease detection. Thus, removing inappropriate and duplicate features from the training set with sequential f
... Show MoreThis paper proposes a novel method for generating True Random Numbers (TRNs) using electromechanical switches. The proposed generator is implemented using an FPGA board. The system utilizes the phenomenon of electromechanical switch bounce to produce a randomly fluctuated signal that is used to trigger a counter to generate a binary random number. Compared to other true random number generation methods, the proposed approach features a high degree of randomness using a simple circuit that can be easily built using off-the-shelf components. The proposed system is implemented using a commercial relay circuit connected to an FPGA board that is used to process and record the generated random sequences. Applying statistical testing on th
... Show MoreThe influence of Diethyl phthalate (DEP) on the optical characteristics of polystyrene solutions in the range between 200 to 400 nm at solvents of different polarities; chloroform, cyclohexane, dichloromethane, and tetrahydrofuran have been recorded. The experimental results showed that the behavior of the photophysical processes of polymer solutions depends on the nature of its environment. The intensity of the absorption and fluorescence spectra depends on the interactions between solvent-solute molecules. The experimental results indicate that the maximum most absorbance bands occur around 262 nm, which depends on the concentration of the quencher. The results did not determine any change in the positions of the most absorption bands.
... Show MorePure blend (PC-PS) and doped blend films with various volume ratio of Coumarin dye were prepared by using casting method. The absorption and transmission spectra for these films were measured using UV/VIS spectrometer technique in order to assessment the type of transition which was found to be indirect transition. The optical energy gap of pure PC was (4.24) eV, pure PS was (4.39) eV, Coumarin dye was (4.08) eV, and pure blend was (4.1) eV. After doping blend with Coumarin dye; the energy gap decreases by (0.06) eV in volume ratio (12) ml. The results showed that absorption coefficient and refractive index affects by doping. When adding the Coumarin dye to the pure blend with different concentrations (12, 24, 36, and 48) ml, the FTIR sp
... Show MoreThe method of powder technology has been utilized for fabrication of ceramic filters. Ceramic filters with interconnected porosity have been achieved via mixes of ceramic powders with addition of glass powders, therefore, interparticle glassy phase is introduced and act as a weld between the crystalline grains in a high porosity microstructure. Tow types of ceramic filters have been produced, the first with high silica content and the other is with high alumina content. Both physical and mechanical properties has been performed and discussed