The optical transmission and absorption spectra in UV-VIS were recorded in the wavelength range 350-800 nm for different glass compositions in the system: (CuO)x (PbO)50-x (Bi2O3)50 (x=2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 20.0). Absorption coefficient {α (λ)}, optical energy gap (Eopt), refractive index (n), optical dielectric constant (ε`), Urbach energy (Ee), constant B and ratio of carrier concentration to the effective mass (N/m) have been reported. The effects of compositions of glasses on these parameters have been discussed. It has been indicated that a small compositional modification of the glasses lead to an important change in all the optical properties including non-linear behavior. The optical parameters were found to be almost the same for different glasses in the same family.
Adsorption is a simplified new way, easy application , economical and environmentally friendly. In which the use of certain types of plants to remove or reduce toxic heavy metals from water. The current study involved the use of a non-living biomass as a powder for local plant available in the Iraqi environment is Phragmites australis .This the study showed the high ability of this plant to remove cadmium and lead ions from the aqueous solutions within variable experimental factors by column bed method which were used to test different sizes of plant powder were (500.1000, 1500 and 2000) μm . These sizes treated with initial concentration of Cd(II), Pb(II) was 25ppm , separately To test the optimum size for maximum adsorption and was 10
... Show MoreOne of the major environmental problems is the pollution of water and soilsby toxic
heavy metals.The aim of current study was estimatation the ability of Eclipta alba
plant for the removal of (Pb) from the polluted water by phytoremedation technique
and study the effect of a number of parameters(Pb concentration, contact time and
pHvalues). The plant showed higher removal efficiency (99.2%) after 7 days of
treatment at 50ppm.The best removal efficiency of Pb 98.95% at 100ppm was
occurred at pH7. The root ability to accumulate Pb was more than the shoot ability,
after 7 days treatment of water and pH=7, they were 2852.5 mg/kg, 2497.5 mg/kg
and 502.5 mg/kg in roots, stems and leaves respectively. These results showe
Thick films of poly(vinyl chloride)(PVC)& PVC doped with Zn(etx)2 salt complex have been prepared by cast method with fixed thickness almost (120±5) Microns. Optical studies were carried out in the wavelengths region(200-900)nm based on absorption & transmition measurement. Optical parameters such as absorption coefficient(?) ,refraction index(n) and extinction coefficient(K) were observed to be effected by adding the dopant.Electrical parameters such as real(?)& imaginary(?) part of dielectric constant were also calculated part of dielectric constant were also calculated from the optical parameters using Maxwell equation.
We have studied the synthesis environment of ambient pressure silica aerogels influence on their resulting morphological and optical properties. Transparent nanoporous silica aerogel was synthesized at ambient pressure using tetraethylorthosilicate precursor via a sol-gel process. Effect of drying control chemical additives and catalyst on physical properties was investigated. Trimethylchlorolsilane was employed as a hydrophobic reagent in the surface modification process. All aerogel samples were prepared utilizing a subcritical procedure under reactant pH fixed at 8.3, using just ammonium hydroxide or together with ammonium fluoride as catalyst. The effects catalyst types as well as drying control chemical additives on the physical pro
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We demonstrate the results of a mathematical model for investigation the nonlinear Stimulated Brillouin Scattering (SBS), which can be employed to achieve high optical amplifier. The SBS is created by interaction between the incident We demonstrate the results of a mathematical model for investigation the nonlinear Stimulated Brillouin Scattering (SBS), which can be employed to achieve high optical amplifier. The SBS is created by interaction between the incident light and the acoustic vibration fiber. The design criteria and the amplification characteristic of the Brillouin amplifier is demonstrated and discussed for fiber Brillouin amplifier using different pump power with different fiber length. The results show, high Brillouin gain can
... Show MoreThis paper deals with a Twin Rotor Aerodynamic System (TRAS). It is a Multi-Input Multi-Output (MIMO) system with high crosscoupling between its two channels. It proposes a hybrid design procedure that combines frequency response and root locus approaches. The proposed controller is designated as PID-Lead Compensator (PIDLC); the PID controller was designed in previous work using frequency response design specifications, while the lead compensator is proposed in this paper and is designed using the root locus method. A general explicit formula for angle computations in any of the four quadrants is also given. The lead compensator is designed by shifting the dominant closed-loop poles slightly to the left in the s-plane. This has the effect
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