Experiments were conducted to study the behavior of the solid particles (proppant) inside the hydraulic fracture during the formation stimulation, and study the effect of the proppant concentration on the hydraulic fracturing process, which lead to bridge and screen-out conditions inside the fractures across the fracture width that restricts fracturing fluid to flow into the hydraulic fracture. The research also studies the effect of the ratio between the fracture size and the average particles diameter “proppant", on fracture bridging. In this study two ratios were considered β= 2 and 3 ,where β=D_t / D_p where: D_t= hydraulic fracture size (width) and Dp=Average particles diameter.

This work pr

A cantilevered piezoelectric beam with a tip mass at its free end is a common energy harvester configuration. This paper introduces a new principle of designing such a harvester which increases the generated voltage without changing the natural frequency of the harvester: The attraction force between two permanent magnets is used to add stiffness to the system. This magnetic stiffening counters the effect of the tip mass on the natural frequency. Three setups incorporating piezoelectric bimorph cantilevers of the same type in different mechanical configurations are compared theoretically and experimentally to investigate the feasibility of this principle. Theoretical and experimental results show that magnetically stiffe

Stripping is one of the major distresses within asphalt concrete pavements caused due to penetration of water within the interface of asphalt-aggregate matrix. In this work, one grade of asphalt cement (40-50) was mixed with variable percentages of three types of additives (fly ash, fumed silica, and phosphogypsum) to obtained an modified asphalt cement to resist the effect of stripping phenomena .The specimens have been tested for physical properties according to AASHTO. The surface free energy has been measured by using two methods namely, the wilhelmy technique and the Sessile drop method according to NCHRP-104
procedures. Samples of asphalt concrete using different asphalt cement and modified asphalt cement percentages(4.1,4.6 an

This paper studies the influence of temperature on the corrosion rate of coated AA6111 aluminum alloy used in vehicle bodies under static and vibration states. The vibration test system was collected laboratory and used for testing of five different types of paints (EASI, Numix, Lesonal, DENSO and Polaron paints) in the 5 % NaCl solution using immersion test method. Lesonal paint provided the best corrosion protection, while DENSO paints show large values of corrosion rate, other coatings exhibit moderate values. Model of paints corrosion was developed to characterize the corrosion processes occur at the surfaces. It is found that corrosion rate obtained at vibration cases is larger than static cases and vibration effect

The aim of the present study is to provide the adequate knowledge about the role of time management in facilitate the work requirements for employees of the administrative department at the Ministry of Higher Education and Scientific Research. The research depend on studying four important dimensions which are (time planning, time organization, time direction and time observation). In addition to study other five dimensions which are (new procedures, clear procedures, short procedures, the available information and the simplicity of the methods

used).Questionnaire sheets consist of (38 questions) distributed to (170) employees and (146)  sheets only were considered in the study. SPSS program was used

The Fylex extract exert a high inhibition effect against A . flavus growth on PDA medium, as the fungus growth was completely inhibited by 100% at a concentration of 0.2 and 0.3% of studied extract, while the lowest inhibition percentage (71%) was found at a concentration of 0.1%. Whereas magnesium oxide nanoparticles showed the highest inhibition ratio of A. flavus (100%) was detected at 0.2% and the lowest inhibition ratio (81.66%) was at concentration 0.5%. Moreover, the addition of G. lucidum powder to PDA medium with a concentration of 2.5 mg increased the inhibition rate of A. flavus growth which was 54.4%, while the lowest inhibition ration (18.22%) was found at a concentration of 1000 mg. The milky liquid (brocade milk) of Calotropi

The importance of the current study  lies in the  importance of the  Tax policy that  being considered one of the most important tools working on fulfilling  the  social,  financial  and economic  goals  and improving  the investment environment  in the country  to become  having the ability to  activate the  national economy. The current study  has  referred  that  (  Has  the  tax planning  practiced by  the Iraqi  contribution  companies  led to increase  the  far-term tax  outcome through  getting  benefit of   the monetary  funds  and expansion in&nbs

Abstract

The aim of the research is to identify the effect of using the self-questioning strategy on the achievement of fourth-grade students in science and the development of their reflective thinking in physics in the city of Baghdad. The research sample was divided into two groups: an experimental group of (20) students and a control group of (20) students. The researchers developed two tools: a test of (40) multiple-choice questions. The second tool is a test to measure the reflective thinking skills of fourth-grade students. It consists of (25) multiple-choice questions distributed on skills as follow: reflection and observation, detection of inaccuracies, reaching conclusions, giving clear explanations, an