The research addressed an analytical field investigation of the locality of meander, the factors responsible of the locality of the meander at certain points of the stream other than others, and the role sequence of these factors in the formation process.
The research revealed that the location of forming the meander was associated closely with the scale structural composition of the bank materials from which the first stage of forming the curved stream, for the inhomogeneous or non-identical opposite banks in their scale structural composition saw an activity of differential corrosion, while the homogeneous and identical opposite banks in their scale structural composition saw an identical corrosion activity in its intensity at both banks. The research investigated in field the presence of scale variation of the materials of opposite banks in the location of forming the meander which was not found at the incurved stream banks by taking samples and analyze them in scale. The analysis results showed that the synclinal bank was with high sand ratio which was the reason behind the activity of corrosion process due to its weak cohesion, high permeability, and highroughness creating an environment of frequent turmoil reverse eddy currents. As to its opposite bank which represented the convex bank, the results of the scale analysis showed its soil to be with high content of mud; therefore, it was resistant to the corrosion activity compared to the synclinal bank, being more cohesive and of weak permeability, it was soft, so it did not create a turmoil eddy motional environment of the aquatic currents. While in the incurved stream, the results of the scale analysis showed that the soil of both opposite banks were identical in its volume content; therefore, the activity of the corrosion process was identical at both banks and its high sand ratio resulted in the expansion of the stream and not its fold.
The research revealed that the circularity of the curved stream imposed the presence of the centrifugal force which appeared in the domains of the circular motion, changing the concentration locations of the currents. As it is well-known, the fastest currents in the river are those which locate far away from the bottom and the banks, and are found in the middle of the stream which we really found in the incurved stream, but due to the control of the centrifugal force, we found that the fastest currents were concentrated at the synclinal banks and that the slowest currents were concentrated at the synclinal banks, which explains logically and realistically due to the contrast of the corrosion and sediment activity in the curved river streams and the presence of centrifugal force was responsible of the development of these streams from fold to curve to turn to cut lake.
The research defined the morphology of the curved stream at any stage of the development stages at the presence of three corrosion units that represent the synclinal banks meeting three sedimentary units represent the convex banks, two of which were opposite to each other represent overall the neck of the stream and the stream in its complete shape was represented by the overall of these corners
The fractional free volume (Fh) in polystyrene (PS) as a function of neutron -irradiation dose has been measured, using positron annihilation lifetime (PAL) method. The results show that Fh values decreased with increasing n-irradiation dose up to a total dose of 501.03× 10-2 Gy.
A percentage reduction of 2.14 in Fh values is noticed after the initial n-dose corresponding to a percentage reduction in the free volume equal to 42.14/Gy.
The total n-dose induces a percentage reduction of 7.26, corresponding to a percentage reduction of 1.45/Gy. These results indicate that cross -linking is the predominant process induced by n-irradiation.
The results suggest that n-irradiation induces structure changes in PS, causing cross-linking
Abstract
The aim of the present work is to control of metal buried corrosion by alteration the media method. This method depended on the characteristics of each media. The corrosion rates in different media (soil, sand, porcelanite stone and gravel) for specimens of low carbon steel were measured by two methods weight loss method and polarization method, weight loss measured by buried specimens in these medias separately for 90 days. The polarization method includes preparing of specimen and salt solutions have electrical resistivity equivalent electrical resistivity of these media. The corrosion rate of two method results in (soil > sand> porcelainte stone> gravel). The lower corrosion rate happene
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In this article the unsteady magnetohydrodynamics oscillating flow of third order fluid with free stream velocity is proposed. It is found that the motion equation is controlled by five dimensionless parameters namely the coecostic parameter 4, viscoelostic parameter ?,acceleration/deceleration c,suction/blowing d and material constants ? . The effect of each of these parameters upon the velocity distribution is analysised
In this reserch Some new substituted and unsubstituted poly imides compounds. were synthesized by reaction of acrylol chloride with different amides (aliphatic and aromatic) in a suitable solvent in the presence amount triethyl amine (Et3N) with heating. The Structure confirmation of all polymers were confirmed using FT-IR,1H-NMR,13C-NMR and UV spectroscopy. Thermal analysis (TG) for some polymers showed their thermal stabilities. Other physical properties including softening points, melting point and solubility of the polymers were also measured
Quadrotors are coming up as an attractive platform for unmanned aerial vehicle (UAV) research, due to the simplicity of their structure and maintenance, their ability to hover, and their vertical take-off and landing (VTOL) capability. With the vast advancements in small-size sensors, actuators, and processors, researchers are now focusing on developing mini UAV’s to be used in both research and commercial applications. This work presents a detailed mathematical nonlinear dynamic model of the quadrotor which is formulated using the Newton-Euler method. Although the quadrotor is a 6 DOF under-actuated system, the derived rotational subsystem is fully actuated, while the translational subsystem is under-actuated. The der
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A total of nine swab samples were collected from inflamed teeth and gingiva of human’soral cavity from a dentist clinic in Baghdad. All specimens were cultured in Mitis Salivarius agar medium and the isolated bacterial pure colonies werethen identified by using VITEK2. Three samples were diagnosed and identified as Staphylococcus lentus. One of the three isolates which showed a distinctive heavy growth on the media was selected for further analysis in this study. Paper disk diffusion method was used to detect the antibacterial activityof three of mouthwash solutions (Zak, Colgate and Listerine). The results showed that “Colgate†was the most active solution with antibacterial activity compared with the other two s
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