Free Space Optics (FSO) plays a vital role in modern wireless communications due to its advantages over fiber optics and RF techniques where a transmission of huge bandwidth and access to remote places become possible. The specific aim of this research is to analyze the Bit-Error Rate (BER) for FSO communication system when the signal is sent the over medium of turbulence channel, where the fading channel is described by the Gamma-Gamma model. The signal quality is improved by using Optical Space-Time Block- Code (OSTBC) and then the BER will be reduced. Optical 2×2 Alamouti scheme required 14 dB bit energy to noise ratio (Eb/N0) at 10-5 bit error rate (BER) which gives 3.5 dB gain as compared to no diversity scheme. Th

The present work divided into two parts, first the experimental side which included the
measuring of the first natural frequency for the notched and unnotched cantilever composite beams
which consisted of four symmetrical layers and made of Kevlar- epoxy reinforced. A numerical
study covers the effect of notches on the natural frequencies of the same specimen used in the
experimental part. The mathematical model for the beam contains two open edges on the upper
surface. The effect of the location of cracks relative to the restricted end, depth of cracks, volume
fraction of fibers and orientation of the fiber on the natural frequencies are explored. The results
were calculated using the known engineering program (ANSY

The aims of the research is to know the role of strategic to manage the human resources in enhancement the process of knowledge management in the Ministry of Transportation , In addition to the effects occurred on outcomes for both the managers and practitioners .

For the purpose of achieving the objectives of the research , the researchers designed a questionnaire that included (40 Points for collecting the primary data from the sample of the research which contained (51) indiviluals. In light of that, the data was to collect and analyzed and hypotheses were tested by using the (SPSS) Program, and a number of statistical techniques was used to attain the goal of the research such as the means ,  Sta

Cumulative lifetime lead (Pb) exposure has been associated with accelerated declines in cognition through the free radical generation and epigenetic effects. Several pieces of literature have identified a correlation between exposure to lead and neurodegenerative disorders. Harwich strain Drosophila melanogaster was exposed to lead acetate for two weeks, and changes in pulse transmission by acetylcholinesterase and systemic redox were evaluated. Besides, molecular docking studies of acetylcholinesterase against Quercetin and its most common derivatives contained in food have been performed. Pharmacokinetic studies on Quercetin and its derivatives have also been performed in silico toxicity. The data obtained showed alterations in antioxi

Mature oil reservoirs surrounded with strong edge and bottom water drive aquifers experience pressure depletion and water coning/cresting. This laboratory research investigated the effects of bottom water drive and gas breakthrough on immiscible CO2-Assisted Gravity Drainage (CO2-AGD), focusing on substantial bottom water drive. The CO2-AGD method vertically separates the injected CO2 to formulate a gas cap and Oil. Visual experimental evaluation of CO2-AGD process performance was performed using a Hele-Shaw model. Water-wet sand was used for the experiments. The gas used for injection was pure CO2, and the “oleic” phase was n-decane with a negative spreading coefficient. The aqueous phase was deionized water. To evaluate the feasibilit

Pure and Fe-doped zinc oxide nanocrystalline films were prepared
via a sol–gel method using -
C for 2 h.
The thin films were prepared and characterized by X-ray diffraction
(XRD), atomic force microscopy (AFM), field emission scanning
electron microscopy (FE-SEM) and UV- visible spectroscopy. The
XRD results showed that ZnO has hexagonal wurtzite structure and
the Fe ions were well incorporated into the ZnO structure. As the Fe
level increased from 2 wt% to 8 wt%, the crystallite size reduced in
comparison with the pure ZnO. The transmittance spectra were then
recorded at wavelengths ranging from 300 nm to 1000 nm. The
optical band gap energy of spin-coated films also decreased as Fe
doping concentra