Hollow core photonic bandgap fibers provide a new geometry for the realization and enhancement of many nonlinear optical effects. Such fibers offer novel guidance and dispersion properties that provide an advantage over conventional fibers for various applications. Dispersion, which expresses the variation with wavelength of the guided-mode group velocity, is one of the most important properties of optical fibers. Photonic crystal fibers (PCFs) offer much larger flexibility than conventional fibers with respect to tailoring of the dispersion curve. This is partly due to the large refractive-index contrast available in the silica/air microstructures, and partly due to the possibility of making complex refractive-index structure over the fiber cross section. In this paper the fundamental physical mechanism has been discussed determining the dispersion properties of PCFs, and the dispersion in a gas filled hollow core photonic crystal fiber has been calculated. We calculate the dispersion of air filled hollow core photonic crystal fiber, also calculate the dispersion of N2 gas filled hollow core photonic crystal fiber and finally we calculate the dispersion of He gas filled hollow core photonic crystal fiber.
The development taking place on the sports field at the general level and in the game of football at the private level, being the most popular game in the world, has reached very advanced stages. The use of modern aids and technology has contributed greatly to this development from the collective and individual aspects, as the goalkeeper is the most important position in the team, the use of devices gave objective readings about the goalkeeper’s ability in terms of skill and physical aspects, as the importance of the research lies in designing an electronic device to measure the degree of bending of the knee angle because of its great importance in developing the skill of catching and dimensions of the high ball for football goalkeepers.
... Show MoreHedging is a linguistic avoidance of full commitment or precision. It is the use of a vague language. The main objectives of this study are to
... Show MoreThe mysterious letters, the philosophy of existence and the meaning of these letters in the Qur'an is one of the mysterious issues that has always occupied the minds of Interpreters. Each Interpreter has tried to provide his own interpretation and understanding of these mysterious letters. Since these letters are part of the surah of the Qur'an and at the same time, the appearance of these letters, unlike other verses, does not indicate meaning, the commentators have approached these verses with their preconceptions. In this article, an attempt has been made to investigate the role of pre-interpreters of descriptors in a descriptive and analytical method in finding the meaning of syllables. However, each of them has tried to interpret th
... Show MoreThe research aims to show the relationship between the use of automated accounting systems technology and its impact on enhancing the efficiency and effectiveness of the internal control system in a sample of Bahraini universities in light of the rapid changes in the electronic business environment. Automated accounting and its impact on enhancing the efficiency and effectiveness of the internal control system, and it is concluded through the analytical study of the research sample that there is a percenta
... Show MoreIn this paper, A.C conductivity of micro and nano grain size- TiO2 filled epoxy composites is measured. The dielectric material used is epoxy resin, while micro and nano-sized titanium dioxide (TiO2) of grain size (1.5μm, and 50nm) was used as filler at low filler concentrations by weight (3%, and 5%). Additionally the effect of annealing temperature range (293-373)º K and at a frequency range of 102-106 Hz on the A.C conductivity of the various specimens was studied.
The result of real permittivity for micro and nanocomposite show that the real permittivity increases with decreasing frequency at range of 102-106Hz. The micron-filled material has a higher real relative permittivity than the nano-filled this is true at all the temper
The present work reports on the performance of three types of nanofiltration membranes in the removal of highly polluting and toxic lead (Pb2+) and cadmium (Cd2+) from single and binary salt aqueous solutions simulating real wastewaters. The effect of the operating variables (pH (5.5-6.5), types of NF membrane and initial ions concentration (10-250 ppm)) on the separation process and water flux was investigated. It was observed that the rejection efficiency increased with increasing pH of solution and decreasing the initial metal ions concentrations. While the flux decreased with increasing pH of solution and increasing initial metal ions concentrations. The maximum rejection of lead and cadmium ion
... Show MoreAn innovative desalination method called electrosorption or capacitive deionization (CDI) has significant benefits for wastewater treatment. This process is performed by using a carbon fiber electrode as a working electrode to remove hexavalent chromium ions from an aqueous solution. The pH, NaCl concentration, and cell voltage were optimized using the Box-Behnken experimental design (BDD) in response surface methodology (RSM) to study the effects and interactions of selected variables. To attain the relationship between the process variables and chromium removal, the experimental data were subjected to an analysis of variance and fitted with a quadratic model. The optimum conditions to remove Cr(VI) ions were: pH of 2, a cell voltage of 4.
... Show MoreA nanocrystalline CdS thin film with 100 nm thickness has been prepared by thermal evaporation technique on glass substrate with substrate temperature of about 423 K. The films annealed under vacuum at different annealing temperature 473, 523 and 573 K. The X-ray diffraction studies show that CdS thin films have a hexagonal polycrystalline structure with preferred orientation at (002) direction. Our investigation showed the grain size of thin films increased from 9.1 to 18.9 nm with increasing the annealing temperature. The optical measurements showed that CdS thin films have direct energy band gap, which decreases with increasing the annealing temperature within the range 3.2- 2.85 eV. The absorbance edge is blue shifted. The absorption
... Show MoreThe research aimed to identify the level of reality of administrative values of sports activities in the Faculties of the university of Baghdad from the point of view of the leaders and those related to the divisions and units of student's activities and the case study method was adopted from the descriptive approach.