Calculations and predication a theoretical formulas for the electron drift velocity in a gas medium are achieved to deduced the electron distribution function for different gas concentrations. The calculations are achieved by using the numerical solution for Boltzmann transport equation in two term approximation, using the NOMAD program for the drift velocity in a gas medium. It's necessary to note that the solution is essentially depending upon the elastic and inelastic collision cross section. In order to fixe a good accuracy for the using cross section it's necessary to calculate the electron distribution function and therefore study their behavior. Results about the electron drift velocity show that a decreasing profile with the increase of the SF6 gas concentration. And also an increasing profile for the drift velocity related to a high nitrogen concentrations. The important applications for these gases are in using them as an insulator in electrical transformers and generators.
In present work an investigation for precise hole drilling via continuous wave (CW) CO2 laser at 150 W maximum output power and wavelength 10.6 μm was achieved with the assistance of computerized numerical controlled (CNC) machine and assist gases. The drilling process was done for thin sheets (0.1 – 0.3 mm) of two types of metals; stainless steel (sst) 321H, steel 33 (st). Changing light and process parameters such as laser power, exposure time and gas pressure was important for getting the optimum results. The obtained results were supported with computational results using the COMSOL 3.5a software code.
The aim: Infection with the hepatitis B virus (HBV) caused by blood transfusion is a big problem throughout the world. The aim of study is to determine the faster and more accurate methods for detection of hepatitis B infections by serological screening and PCR- amplification. Materials and methods: A total of 140528 donors were tested for HBsAg and total anti-HBc from January to October 2021 in Iraq’s National Blood Transfusion Center; however, only 100 samples with HBsAg (-) and anti-HBc (+) were collected and tested for HBV DNA using quantitative real-time PCR. Results: From 2015 to 2021, the percentage of HBsAg positive donors was 0.33 percent in 2015, 0.32 percent in 2016, 0.30 percent in 2017, 0.28 percent in 2018, 0.23 pe
... Show MoreBackground:Â Various fluids in the oral environment can affect the surface roughness of resin composites. This in vitro study was conducted to determine the influence of the mouth rinses on surface roughness of two methacrylate-based resin (nanofilled and packable composite) and siloraine-based resin composites.
Materials and methods: Disc-shaped specimens (12 mm in diameter and 2mm in height) were prepared from three types of composi
... Show MoreCdSe/CdS Core/shell nanostructures were prepared through the chemical synthesis method. XRD ,FESEM and TEM investigations confirmed the formation of core/shell structure for the sample. The AFM measurement was employed to reveal the morphology of the prepared thin films. Optical characterizations of the quantum dots were done by UV-visible and photoluminescence spectra. It was found that the quantum dots prepared has good optical properties. Due to the presence of shell coating on core CdSe, the energy gap of the core/shell nanomaterial were increased from 2.2 to 2.3eV. The resulted QDs are a promising candidate for photovoltaic and biosensor applications.
Baghdad Metro is a vital project to fulfill the rapidly increased traffic volume requirements. The proposed metro will connect both sides of Baghdad City, passing under the Tigris River. This study is employed finite elements software (PLAXIS 3D) to evaluate the seepage force developed around the sub-river segment during different construction stages and for other water levels of Tigris. The study found that when the water level changes from maximum to minimum, the developed seepage force decreases by (8 to 13%) and (22 to 27%) respectively. The seepage forces were found to be maximum during the excavation stage. The concrete lining process led to a noticeable reduction in seepage forces at all locations. The study also
... Show MoreThere is an evidence that channel estimation in communication systems plays a crucial issue in recovering the transmitted data. In recent years, there has been an increasing interest to solve problems due to channel estimation and equalization especially when the channel impulse response is fast time varying Rician fading distribution that means channel impulse response change rapidly. Therefore, there must be an optimal channel estimation and equalization to recover transmitted data. However. this paper attempt to compare epsilon normalized least mean square (ε-NLMS) and recursive least squares (RLS) algorithms by computing their performance ability to track multiple fast time varying Rician fading channel with different values of Doppler
... Show MoreThe current research focuses on the antioxidant activity, phytochemical, and inorganic content of five common medicinal plants: Asian pigeonwings, lemon balm, lemongrass, ginger, and turmeric. According to the phytochemical screening, flavonoids were present in all plants; tannins were present in lemon balm and lemongrass, saponins were present in all plants except lemongrass, and anthraquinone glycosides were detected only in turmeric. The aqueous extracts from lemon balm, Asian pigeonwings, and the methanolic extract from turmeric had the highest phenolic content, respectively. The inorganic composition of plants was determined using energy dispersive X-ray fluorescence. Asian pigeonwings, ginger and turmeric are mainly compos
... Show MoreMoisture damage is described as a reduction in stiffness and strength durability in asphalt mixtures due to moisture. This study investigated the influence of adding nano silica (NS) to the Asphalt on the moisture susceptibility of hot-mix-asphalt (HMA) mixtures under different aging conditions. NS was mixed with asphalt binder at concentrations of 2%, 4%, and 6% by weight of the binder. To detect the microstructure changes of modified Asphalt and estimate the dispersion of NS within the Asphalt, the field emission scanning electron microscope (FE-SEM) was used. To examine the performance of Asphalt mixed with NS at different aging stages (short-term and long-term aging), asphalt mixture tests such as Marshall stability,
... Show MoreA structural and engineering geological study of rock slope stability was carried out in six stations that lie in the Southwest of Baranan mountain, along Sirwan road. The rock slopes and discontinuities were surveyed at each of these stations, and the relationships with failures were determined. The slopes were classified on the basis of (Al-Saadi, 1981), and the rocks were described in engineering terms according to (Anon, 1972) and (Hawkins, 1986), Stereographic projection was made using software (GEOrient 9.5.0) to represent the field data that were recorded in order to understand the situation in the six stations (sites) that were chosen along Sirwan road near Darbandikhan dam, the failures' types were recorded during field study we
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