A two-dimensional computational study had been performed regarding aerodynamic forces and pressures affecting a cambered inverted airfoil, CLARK-Y smoothed with ground effects by solving the Reynolds-averaged Navier-Stokes equations, using the commercial software COMSOL Multiphysics 5.0 solver. Turbulence effects are modeled using the Menter shear-stress transport (SST) two-equation model. The negative lift (down-force), drag forces and pressures surface were predicted through the simulation of wings over inverted wings in different parameters namely; varying incidences i.e. angles of attack of the airfoils, varying the ride hide from the ground covering various force regions, two-dimensional cross-section of the inverted front wings to be fixed on nose of a race car- and varying speeds of initial airflow (Reynolds number). The results show that the down-force increases as the angle of attack increases; however, if an inverted wing is fixed on a car at high angles of attack the wing starts to stall which is not a desired condition that affects the vehicle stability and performance. As the ride height was reduced, the down-force was increased; at clearances between the suction surface and the ground of less than 0.2 of the chord length c, the down-force is significantly higher. Very close to the ground, at a ride height of less than 0.1c, down-force decreases as the wing stalls. Also, down-force increases as the free-stream velocity (Reynolds number) increases. The pressures for lower and upper surface of the wing increased with increasing both of angle of attack and ride height, but remains relatively ineffective with varying the speeds.
The process of cognitive representation includes mental activities such as perception, concepts formation and decision making leading to formation of Cognitive representation where the need for Cognition is one of basic humane needs promoting individuals to have more information.
This Study aims to measure the level of Cognitive representation among gifted Schools, the level of need for Cognition among them, recognize statistical Significant differences with Cognitive representation according to gender Variable and recognize the Correlation between Cognitive representation and the need for Cognition among giftel schools . The sample Consists of subsample of mair application one Consisting of( 400) students, noting that the first sampl
Epstein-Barr Virus (EBV) infection is associated with broad spectrum of clinical manifestationsdepending on the immune status of the host, To analyze their possible role in the complication ofautoimmune hepatitis, we investigated (30) female patients with autoimmune hepatitis type-1 of(10-40)years and 25 healthy female of same ages(control groups). Both groups were carried outto measure the levels of EBV-CA IgM, IgG Ab, EBV-EA IgM, IgG Ab, and EBV-NA IgM, IgGAb using indirect immunoflourescent assay (IFAT).The prevalence of EBV-CA IgM, IgG Ab were(10%,20%) and EBV-EA IgM, IgG Ab were (10% and20%) respectively, while the prevalence ofEBV-NA IgG Ab was( 3.33%) and there are no prevalence of EBV-NA IgM Ab. There weresignificant differences (P
... Show MoreBackground: low back pain is one of the most common public health problems and of the most common musculoskeletal complaint. Many risk factors have been considered for developing low back pain include smoking, obesity and sedentary lifestyle.
Aim of study: To evaluate smoking, obesity, and sedentary lifestyle associations with low back pain in young adults aged (18 – 39 years).
Methods: a comparative cross sectional study for young adults aged 18 – 39 years, participants with low back pain as a symptom constitutes the first group, others free of this symptom considered as the control group. Age and gender matched in both groups. Smoking, obesity and sedentary life sty
... Show MoreA simple , sensitive and accurate spectrophotometric method for the trace determination of bismuth (III) has been developed .This method is based on the reaction of bismuth (III) with arsenazo(III) in acid solution (pH=1.9) to form a blue water soluble complex which exhibits maximum absorption at 612nm .Beer's law is obeyed over the concentration range of 2-85 ?g bismuth (III) in a final volume of 20 mL( i.e. 0.1 – 4.25?g.mL-1) with a correlation coefficient of (0.9981) and molar absorptivity 1.9×104 L.mol-1.cm-1 . The limit of detection (LOD) and the limit of quantification (LOQ) are 0.0633 and 0.0847 ?g.mL-1 , respectively . Under optimum conditions,the stoichiometry of the reaction between bismuth (III) and arsenazo(III) r
... Show MoreSalt stress negatively affects germination and seedling growth. Sorghum cultivars (Bohuth70, Inqath and Rabeh), seed soaking in dry yeast extract (3, 6 and 9 g l-1) in addition to dry seeds and electrical conductivity (4, 10 and 16 dS m-1) were studied. Traits of germination ratio at first and final counts, lengths of radicle and plumule, seedling dry weight and seedling vigour index were studied. The cultivar of Bohuth70 and concentration of yeast extract (9 g l-1) were superior at all studied traits, while all traits values were reduced with increased saline stress. The combination (Bohuth70×9×4) was superior to most other treatments at first and final counts, radicle length and seedling dry weight, while superiority of plumule length a
... Show MoreThis paper provides an attempt for modeling rate of penetration (ROP) for an Iraqi oil field with aid of mud logging data. Data of Umm Radhuma formation was selected for this modeling. These data include weight on bit, rotary speed, flow rate and mud density. A statistical approach was applied on these data for improving rate of penetration modeling. As result, an empirical linear ROP model has been developed with good fitness when compared with actual data. Also, a nonlinear regression analysis of different forms was attempted, and the results showed that the power model has good predicting capability with respect to other forms.