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 the highest value of the voltage was recorded at 46 ns and the minimum voltage required for insulation breakdown was 112 kV at 200 ns. It was revealed that the streamer velocity recorded the highest value when the streamer reaches the plate electrode and the lowest value when the streamer begins to propagate. Results also showed that the streamer discharge was dominated by positive ions while the negative ions have a low effect.
Optimization is the task of minimizing or maximizing an objective function f(x) parameterized by x. A series of effective numerical optimization methods have become popular for improving the performance and efficiency of other methods characterized by high-quality solutions and high convergence speed. In recent years, there are a lot of interest in hybrid metaheuristics, where more than one method is ideally combined into one new method that has the ability to solve many problems rapidly and efficiently. The basic concept of the proposed method is based on the addition of the acceleration part of the Gravity Search Algorithm (GSA) model in the Firefly Algorithm (FA) model and creating new individuals. Some stan
... Show MoreBackground: Nursing interventions tailored to the smoking triggers in patients with non-communicable chronic diseases are essential. However, these interventions are scant due to the nature of factors associated with smoking cessation and the poor understanding of the effect of nurse-led intervention in Iraq.Purpose: This study aimed to determine the dominant smoking triggers and examine the effects of a tailored nursing intervention on smoking behavior in patients with non-communicable chronic diseases.Methods: Convenience samples of 128 patients with non-communicable chronic diseases, male and female patients, who were 18-70 years old, were recruited in this quasi-experimental, randomized comparative trial in the outpatient clinic
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Find interested in the harmonization of variables and determinants of supply chain planning needs of the material, leading to the results start effective supply chain management, and end up quickly modify the sizes to suit the demand and turnover in the market. As well as identifying relationships between variables, and type of relationship used by the company with the processors and their feasibility, and indicate the level of interest and willingness to redesign the supply chain Company for Electrical Industries and build an integrated model for supply chain with the MRP system can be applied in the company.
Research depend on quantitative and descriptive method, It
... Show MoreClustering is an unsupervised learning method that classified data according to similarity probabilities. DBScan as a high-quality algorithm has been introduced for clustering spatial data due to its ability to remove noise (outlier) and constructing arbitrarily shapes. However, it has a problem in determining a suitable value of Eps parameter. This paper proposes a new clustering method, termed as DBScanBAT, that it optimizes DBScan algorithm by BAT algorithm. The proposed method automatically sets the DBScan parameters (Eps) and finds the optimal value for it. The results of the proposed DBScanBAT automatically generates near original number of clusters better than DBScanPSO and original DBScan. Furthermore, the proposed method
... Show MoreOrthophoto provides a significant alternative capability for the presentation of architectural or archaeological applications. Although orthophoto production from airphotography of high or lower altitudes is considered to be typical, the close range applications for the large-scale survey of statue or art masterpiece or any kind of monuments still contain a lot of interesting issues to be investigated.
In this paper a test was carried out for the production of large scale orthophoto of highly curved surface, using a statue constructed of some kind of stones. In this test we use stereo photographs to produce the orthophoto in stead of single photo and DTM, by applying the DLT mathematical relationship as base formula in differenti
... Show MoreAn Auto Crop method is used for detection and extraction signature, logo and stamp from the document image. This method improves the performance of security system based on signature, logo and stamp images as well as it is extracted images from the original document image and keeping the content information of cropped images. An Auto Crop method reduces the time cost associated with document contents recognition. This method consists of preprocessing, feature extraction and classification. The HSL color space is used to extract color features from cropped image. The k-Nearest Neighbors (KNN) classifier is used for classification.
Background:-Anorectal malformation is a congenital anomaly of different varieties and its correction needs good experience , knowledge about this varieties and specific surgical tools,
otherwise the child may lose his the only chance to live normally without disastrous complication like incontinence.
Objective:-assessment of the advantage of this procedure in management of anorectal malformations and the percentage for anal continence.
Patients and methods:-. This study was carried out in the child's central teaching hospital in Baghdad total number (70) cases were included in the study, 37 males and 33 females: aged 7 days to 6 years. They attended the hospital between October 1998-october 2004.
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