The dimensions of bubbles were measured in a stirrer tank electrochemical reactor, where the analysis of the bubble size distribution has a substantial impact on the flow dynamics. The high-speed camera and image processing methods were used to obtain a reliable photo. The influence of varied air flow rates (0.3; 0.5; 1 l/min) on BSD was thoroughly investigated. Two types of distributors (cubic and circular) were examined, and the impact of various airflow rates on BSD was investigated in detail. The results showed that the bubbles for the two distributors were between 0.5 and 4.5 mm. For both distributors at each airflow, the Sauter mean diameter for the bubbles was calculated. According to the results, as the flow rate raised, the bubble size for cubic distributors increased from 2.35 to 2.41 mm and for circular distributors from 2.76 to 2.88 mm.
An experimental model is used to simulate the loss of soil lateral confinement due to excavation nearby an individual axially loaded pile. The effects of various parameters, such as the horizontal distance of excavation, depth of excavation and pile slenderness ratios are investigated. The experimental analysis results showed the effect of excavation is more remarkable as the horizontal distance of excavation becomes closer to the pile than half pile length. The effect of excavation diminishes gradually as the horizontal distance increases beyond that distance for all the investigated pile slenderness ratios and depths of excavation. The pile head deflection, settlement and bending moments along pile increase with decreasing horizontal d
... Show MoreThis Action research aimed at Assisting Students of Faculty of Educational Sciences at Al-Quds Open University to design computerized lessons using the Power Point software and according to ADDIE model. The study sample consisted of 40 students who were taking a course titled Technology of Education during the second semester of the 2014-2015 academic year and three academic instructors . To collect the required date , the researchers used focus group technique and structured interviews to get information from the 40 students and the three academic instructors involved in the course Technology of Education in QOU /Nablus Branch. In addition to these methods, a workshop with a guiding checklist was employed t
... Show MoreAn integrated GIS-VBA (Geographical Information System – Visual Basic for Application), model is developed for selecting an optimum water harvesting dam location among an available locations in a watershed. The proposed model allows quick and precise estimation of an adopted weighted objective function for each selected location. In addition to that for each location, a different dam height is used as a nominee for optimum selection. The VBA model includes an optimization model with a weighted objective function that includes beneficiary items (positive) , such as the available storage , the dam height allowed by the site as an indicator for the potential of hydroelectric power generation , the rainfall rate as a source of water . In a
... Show MoreBACKGROUND: Keratoconus is a progressive non inflammatory bilateral (usually asymmetric) ectatic corneal disease characterized by paraxial stromal thinning ,weakening that lead to corneal surface distortion ,vision loss primarily from irregular astigmatism and myopia and secondly from corneal scar. OBJECTIVE: To evaluate visual and refractive outcomes after intracorneal continuous ring (ICCR) implantation combined with intrapocket corneal collagen cross linking in patient with keratoconus. Setting: Eye Specialty Private Hospital, Baghdad, Iraq. METHODS: This study assessed the results of implantation of Myoring ICCR combined with CXL in 40 eyes with KC. Outcome measures include UDVA,CDVA(spectacle correction),refraction, complications and s
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In this work, an experimental investigation has been done for heat transfer by natural-convection through a horizontal concentric annulus with porous media effects. The porous structure in gap spacing consists of a glass balls and replaced by plastic (PVC) balls with different sizes. The outer surface of outer tube is isothermally cooled while the outer surface of inner tube is heated with constant heat flux condition. The inner tube is heated with different supplied electrical power levels. Four different radius ratios of annulus are used. The effects of porous media material, particles size and annulus radius ratio on heat dissipation in terms of average Nusselt number have been analyzed. |
: Porous silicon (n-PS) films can be prepared by photoelectochemical etching (PECE) Silicon chips n - types with 15 (mA /cm2), in15 minutes etching time on the fabrication nano-sized pore arrangement. By using X-ray diffraction measurement and atomic power microscopy characteristics (AFM), PS was investigated. It was also evaluated the crystallites size from (XRD) for the PS nanoscale. The atomic force microscopy confirmed the nano-metric size chemical fictionalization through the electrochemical etching that was shown on the PS surface chemical composition. The atomic power microscopy checks showed the roughness of the silicon surface. It is also notified (TiO2) preparation nano-particles that were prepared by pulse laser eradication in e
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