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 fibe

The rate of gas induction was measured in gas-inducing type mechanically agitated contactors provided with two impellers. A reactor of 0.5 m i.d. was used with a working capacity of 60 liters of liquid. Tap water was used as the liquid phase, and air was used as the gas phase. The bioreactor mixing system consists of two equal diameter stirrers; the top impeller is shrouded-disk/curved-blade turbine with six evacuated bending blades, while the bottom impeller was disk turbine. The impeller speed was varied in the range of 50 to 800 rpm. The ratio of impeller diameter to tank diameter (D/T) and the submergence (S) of upper impeller from the top were varied. The effects of clearance of lower impeller from the tank bottom (C₂) an

2 - 5,5 cm mosquito fishes (Gambusia affinis) were collected from brooks of Baghdad university . This study aimed to identify the histological structure and embryonic development of the gas bladder . The results revealed that the gas bladder of the adult fish consists of single chamber, paraphysoclistous , and its wall consist of three layers. The primordium of the gas bladder appears in 2,5 mm fish embryo as an evagination from the right side of endoderm of foreguts wall. This primordium consists of two thecae, inner, is simple columnar epithelium and outer originates from undifferentiated mesoderm. Simultaneously with the appearance of gas gland in the ventral side of the sac in 4 mm embryo, morphological and histological chan

The adsorption isotherms and kinetic uptakes of CO₂ were measured. Adsorption isotherms were measured at two temperatures 309 K and 333 K and over a pressure range of 1 to 7 bar. Experimental data of CO₂ adsorption isotherms were modeled using Langmuir, Freundlich and Temkin. Based on coefficient of correlation it was found that Langmuir isotherm model was well suited with the experimental data of CO₂ adsorption isotherms.  In addition, Adsorption kinetic of CO₂ mixture with N₂ containing 10 % by volume CO₂ and 90 % by volume N₂ were determined in a temperature 36 °C and under the atmospheric pressure .When the flow rate was increased from

Polyaniline organic Semiconductor polymer thin films have been prepared by oxidative polymerization at room temperature, this polymer was deposited on glass substrate with thickness 900nm, FTIR spectra was tested , the structural,optical and electrical properties were studied through XRD ,UV-Vis ,IR measurements ,the results was appeared that polymer thin film sensing to NH3 gas.