Hydrophobic silica aerogels were successfully preparation by an ambient pressure drying method from sodium silicate (Na2SiO3) with different pH values (5, 6, 7, 8, 9 and 10). In this study, acidic HCl (1M), a basic NH4OH (1M) were selected as a catalyst to perform the surface modification in a TMCS (trimethylchlorosilane) solution. The surface chemical modification of the aerogels was assured by the Fourier transform infrared (FTIR) spectroscopic studies. Other physical properties, such as pore volume and pore size and specific surface area were determined by Brunauer-Emmett- Teller (BET) method. The effect of pH values on the bulk density of aerogel. The sol–gel parameter pH value in the sol, have marked effects on the physical proper

This study is dedicated to investigate the effects of initial laser intensity on the nonlinear optical properties of the laser dye DQOCI dissolved in methanol with a concentration of 10 ^-5 M and doped with PMMA film. The properties were studied by using open and closed aperture Z-scan technique, with different levels of initial intensity (I₀), excited by continuous diode solid-state laser at a wavelength of 532 nm. Three lenses of different focal lengths were employed to change the radius of the Gaussian laser beam and then change the initial intensity. For I₀= 6.83 and 27.304 kWatt/cm², the Z-scan curves show a saturation of absorption (SA) known as the negative type of nonlinearity, in which

Spray pyrolysis technique was used to make Carbon60-Zinc oxide (C60-ZnO) thin films, and chemical, structural, antibacterial, and optical characterizations regarding such nanocomposite have been done prior to and following treatment. Fullerene peaks in C60-ZnO thin films are identical and appear at the same angles. Following the treatment of the plasma, the existence regarding fullerene peaks in the thin films investigated suggests that the crystallographic quality related to C60-ZnO thin films has enhanced. Following plasma treatment, field emission scanning electron microscopy (FESEM) images regarding a C60-ZnO thin film indicate that both zinc oxide and fullerene particles had shrunk in the size and have an even distribution. In addition

In this research study the effect of irradiation by (CW) CO2 laser on some optical properties of (Cds) doping by Ni thin films of (1)µm thickness has been prepared by heat evaporation method. (X-Ray) diffraction technique showed the prepared films before and after irradiation are ploy crystalline hexagonal structure, optical properties were include recording of absorbance spectra for prepared films in the range of (400-1000) nm wave lengths, the absorption coefficient and the energy gap were calculated before and after irradiation, finally the irradiation affected (CdS) thin films by changing its color from the Transparent yellow to dark rough yellow and decrease the value absorption coefficient also increase the value of energy gap.

     Zinc oxide films (ZnO) are prepared by an electrolysis technique and without vacuum and then annealed atvarious temperatures (300,400,500)^OC for an hour. The structural analysis performed by X-Ray diffraction (XRD) shows,dominant orientation of this films is plane (101), has a hexagonal structure and  polycrystalline pattern and it was is found that the crystal size increases(24,29) nm at annealing temperatures (300, 400)° C, but the crystal size decreases to (20 nm) at annealing temperature (500 ° C). As the results of a surface nature study of these films showed by examining the atomic force microscope (AFM), the grain  size increases from (60.79 to 88.11) nm, and the surface roughnes

Optical spectrum of SN1987A at days 4 from the explosion and its light curve through the first 1444 days after the explosion have been studied. The hydrogen lines present in the spectrum confirms the general characteristics of Type II SN that occur due to core collapse of massive star. Each of the total mass ejected from the explosion and the amount of the total mass of Nickel radioactive isotopes that produced during the explosion as well as the initial velocity of the ejecta and the explosion energy have been determined and compared with different observed and calculated models obtained by different researchers and it’s found that, about 8.8 Mʘ of the progenitor envelope mass had been ejected during the explosion and it’s mixed with

The present research had dealt with preparing  bars  with the length of about  (13 cm) and  adiametar  of  (1.5 cm) of composite materials with metal  matrix  represented by (Al-Cu-Mg) alloy cast enforced by (ZrO₂) particles with chosen weight  percentages (1.5, 2.5 ,3.5, 5.5 %). The base  cast and the composite  materials were prepared by casting method by uses vortex  Technique inorder to  fix up (ZrO₂) particles in homogeneous way on  the  base cast. In addition to  that, two main groups of composite materials were prepared depending on the particles size of (ZrO₂) , respectively.       &n

The specifications of lubricating oil are fundamentally the final product of materials that have been added for producing the desired properties. In this research, spherical nanoparticles copper oxide (CuO) and titanium oxides (TiO₂) are added to SAE 15W40 engine oil to study the thermal conductivity, stability, viscosity of nano-lubricants, which are prepared at different concentrations of 0.1%, 0.2%, 0.5%, and 1% by weight, and also their pour point, and flash point as five quality parameters. The obtained results show that CuO nanoparticles in all cases, give the best functionality and effect on engine oil with respect to TiO₂. With 0.1 wt. % concentration, the thermal conductivity of CuO/oil and TiO₂/