In this paper, a numerical analysis was carried out using finite element method to analyse the mechanisms for streamer discharges. The hydrodynamic model was used with three charge carriers equations (positive ion, negative ion and electron) coupled with Poisson equation to simulate the dynamic of streamer discharge formation and propagation. The model was tested within a 2D axisymmetric tip-plate electrodes configuration using the transformer oil as the dielectric liquid. The distance between the electrodes was fixed at 1 mm and the applied voltage was 130 kV at 46 ns rising time. Simulation results showed that the time has a clear effect on the streamer propagation along the symmetry axis. In addition, it was observed that t

The nature of the dark sector of the Universe remains one of the outstanding problems in modern cosmology, with the search for new observational probes guiding the development of the next generation of observational facilities. Clues come from tension between the predictions from Λ cold dark matter (ΛCDM) and observations of gravitationally lensed galaxies. Previous studies showed that galaxy clusters in the ΛCDM are not strong enough to reproduce the observed number of lensed arcs. This work aims to constrain the warm dark matter (WDM) cosmologies by means of the lensing efficiency of galaxy clusters drawn from these alternative models. The lensing characteristics of two samples of simulated clusters in the Λ warm dark matter and ΛCDM

In this research, a factorial experiment (4*4) was studied, applied in a completely random block design, with a size of observations, where the design of experiments is used to study the effect of transactions on experimental units and thus obtain data representing experiment observations that The difference in the application of these transactions under different environmental and experimental conditions It causes noise that affects the observation value and thus an increase in the mean square error of the experiment, and to reduce this noise, multiple wavelet reduction was used as a filter for the observations by suggesting an improved threshold that takes into account the different transformation levels based on the logarithm of the b

    The current research discusses "The Relationship critical factors for knowledge transfer in strategic success opportunities", the attention have been increased on knowledge transfer and strategic success subjects because on being one of the important and contemporary issues, which have a significant impact on the existence of organizations and its future. The research aims to identify the critical factors for knowledge transfer in private high education environment which enables (the college community surveyed) to achieve strategic success, also the research sought to answer questions related to research problem by testing a number of major and minor hypothes in correlation, in order to test the hypotheses I us

The drought is a globally phenomenon, its influence will convert large parts of Middle East and North Africa (MENA) region into hot dry deserts under the expectations of the climate change scenarios. Climate limitations, soil erosion affected by weather properties such as unequally and limited rainfall; temperature changing and wind, unsuitable irrigation techniques, excessive grazing, agricultural expansion against to the natural habitats, extensively clearance of natural vegetation, and soil salinity had all contributed to land degradation, reduced water supplies, and limited agricultural production in Iraq. It is estimated that nearly 54.3 % of Iraq's area is threatened by desertification problems.
In this research, for Iraq the Cl

Shehadt 683 fish of different fish present in the tank Haditha Dam during the period of February 1993 and the end Maes 1994 to identify the nutritional content of the digestive tract or the stomach for these fish and their impact on the environment of the tank and found that Fish fine linen and Alhalg animal feeding predators feed on small fish, mainly the fish brown plantnutrition

In this paper, the blow-up solutions for a parabolic problem, defined in a bounded domain, are studied. Namely, we consider the upper blow-up rate estimate for heat equation with a nonlinear Neumann boundary condition defined on a ball in Rn.

The current research aims to reveal the strength of education and the direction of the relationship between the formal thinking and learning methods of Kindergarten department students. To achieve this objective, the researcher developed a scale of formal thinking according to the theory of (Inhelder & Piaget 1958) consisting of (25) items in the form of declarative phrases derived from the analysis of formal thinking skills based on a professional situation that students are expected to interact with in a professional way. The research sample consisted of (100) female students selected randomly who were divided into four groups based on the academic stages, the results revealed that The level of formal thinking of the main sample is