The free electron laser is considered one of these important and advanced inventions because it provides a laser beam within various wavelengths of the electromagnetic spectrum. In any laser system device, several parameters must be available on which the efficiency and performance of the laser system are dependent. The Pierce parameter is one of the important parameters in measuring the performance quality of the free electron laser. In this paper, the simulation results were obtained using the MATLAB program to show the important effect of the Pierce parameter on the performance of the free electron laser system. The simulation results showed that the values of the Pierce parameter ranged between (0.01 - 0.03) for the laser beam with long wavelengths, while it ranged between (0.001-0.0001) for the short wavelengths. The results showed an increase in the efficiency values of the free electron laser system with increasing the values of the Pierce parameter, which represents the ratio between the saturation power and the power of the electron; therefore, it can be used as a specific threshold to measure the efficiency of the laser system. Additionally, the simulation of the Pierce parameter has a direct relation to the small signal gain per unit length.
In this research the electrical conductivity and optical measurements were made on the Iron Oxide (Fe2O3) films prepared by chemical spray pyrolysis method as a function of thickness (250, 350, 450, and 550)  20 nm. The measurements of electrical conductivity (σ), activation energies (Ea1, Ea2),and optical constant such as absorption coefficient, refractive index, extinction coefficient and the dielectric constants for the wavelengths in the range (300-900) nm have been investigated on (Fe2O3) thin films as a function of thickness. All films contain two types of transport mechanisms, and the electrical conductivity (σ) increases whereas the activation energy (Ea) would decrease as the films thi
... Show MoreThe study aims to investigate the relationship between the gender diversity of board director, the accounting conservatism and firm value in Iraqi firms. The sample was represented by 30 Iraqi firms listed on the Iraqi market over the period 2017. The research was based on the main hypothesis that gender diversity has a positive relationship with conservatism and firm value, that conservatism as an intermediate variable will enhance the positive relationship between gender diversity and firm value. The study reached results that support the research hypotheses. The appointment of females to the board helps improve the provision of conservative accounting information and avoids overstate when reporting earnings. Based on these res
... Show MoreBackground: Wound healing is a complicated, interactive, integrative process involving cellular and chemotactic activity, the release of chemical mediators and associated vascular response which includes number of phases: inflammatory phase, proliferative phase and remodeling phase. Low level laser therapy can be more effective in the three overlapping phases of wound healing. Biostimulation appears to have an effect on the cellular level, by increasing cellular function and stimulating various cells. The aim of present study was to evaluate histologically the effect of 780-805 diode laser the intensity of inflammation and pattern of epithelization in mice model. Material and methods: The experimental study was performed on ninety six white
... Show MoreThirty females' albino mice with average body weight of 25-30gm and 10-14 weeks old were used to investigate the toxicity of the oral administration of ampiroxicam on liver. The animals were given (single dose) of drug and were divided into three groups (10mice / group), control group were given distilled water, the two remaining groups ( treated group2 were administered by 20 mg/kg of ampiroxicam for one month and treated group3 were administrated by20 mg/kg of ampiroxicam for tow month). The results showed that the changes in of tissue of liver in treated animals include: degeneration of hepatocyte and hepatic sinusoidal dilation, also lymphocyte infiltration, necrosis, dead cell, detachment of basement membranes and hypertrophy while
... Show MoreElectro-kinetic remediation technology is one of the developing technologies that offer great promise for the cleanup of soils contaminated with heavy metals. A numerical model was formulated to simulate copper (Cu) transport under an electric field using one-dimensional diffusion-advection equations describing the contaminant transport driven by chemical and electrical gradients in soil during the electro-kinetic remediation as a function of time and space. This model included complex physicochemical factors affecting the transport phenomena, such as soil pH value, aqueous phase reaction, adsorption, and precipitation. One-dimensional finitedifference computer program successfully predicted meaningful values for soil pH profiles and Cu
... Show MoreUnderstanding of in-situ stress profiles and orientations plays a vital role in designing a successful hydraulic fracturing treatment. This paper is an attempet to examine the effect of lithology and in situ stress on geometery of hydraulic fractures. A hydraulic fracturing design simulator software called FracproPT with various capabilities for designing most of hydraulic fracture was used for simulate and optimize the hydraulic fracturing. For studying purpose, three different cases of stress gradient contrast between different formations are considered in this study (0.4, 0.5 and 0.75 psi/ft). The results obtained from the simulator showed that lithologies surrounding the pay zone have an effect on the fracture
... Show MoreIn this research, the effect of changing the flood level of Al-Shuwaija marsh was studied using the geographic information systems, specifically the QGIS program, and the STRM digital elevation model with a spatial analysis accuracy of 28 meters, was used to study the marsh. The hydraulic factors that characterize the marsh and affecting on the flooding such as the ranks of the water channels feeding the marsh and the degree of slope and flat areas in it are studied. The area of immersion water, the mean depth, and the accumulated water volume are calculated for each immersion level, thereby, this study finds the safe immersion level for this marsh was determined.
The interests toward developing accurate automatic face emotion recognition methodologies are growing vastly, and it is still one of an ever growing research field in the region of computer vision, artificial intelligent and automation. However, there is a challenge to build an automated system which equals human ability to recognize facial emotion because of the lack of an effective facial feature descriptor and the difficulty of choosing proper classification method. In this paper, a geometric based feature vector has been proposed. For the classification purpose, three different types of classification methods are tested: statistical, artificial neural network (NN) and Support Vector Machine (SVM). A modified K-Means clustering algorithm
... Show MoreThis book presents the problem of tooth decay due to bacteria Streptococcus mutans one of methods of treatment using 3 extracts of S. persica (miswak) (aqueous, acetone and methanol) and prove its effectiveness and its impact on the gtf (B, C, and D) genes that code the glucosyltransferase (Gtf) enzymes that cause decay membrane compared to the usual means used for the prevention of tooth decay
The study attempts to identify 1) the habits of playing video games among students, 2) the effect of playing video games on students’ academic achievement, 3) the statistically significant differences among students in regard of (gender, time of playing video games, number of hours). To this end, a five-likert scale questionnaire included four questions was applied to (250) male and female students chosen randomly from the second-intermediate stage at Al-Karakh side secondary schools. The findings revealed that students play games only on holidays and less than an hour daily, which means playing games does not affect their academic achievement. Additionally, the findings found there is a significant difference between male and female i
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