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Aircraft Lateral-Directional Stability in Critical Cases via Lyapunov Exponent Criterion
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Based on Lyapunov exponent criterion, the aircraft lateral-directional stability during critical flight cases is presented. A periodic motion or limit cycle oscillation isdisplayed. A candidate mechanism for the wing rock limit cycle is the inertia coupling between an unstable lateral-directional (Dutch roll) mode with stable longitudinal (short period) mode. The coupling mechanism is provided by the nonlinear interaction of motion related terms in the complete set equations of motion. To analyze the state variables of the system, the complete set of nonlinear equations of motion at different high angles of attack are solved. A novel analysis including the variation of roll angle as a function of angle of attack is proposed. Furthermore the variation of Lyapunov exponent parameter as function of time is introduced. The numerical result indicated that the system became lightly damped at high angle of attack with increasing the amplitude of aircraft state variables limit cycle. A good agreement between the numerical result and published work is obtained for the onset of limit cycle oscillation, almost at .

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Publication Date
Thu Jun 30 2016
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
The Effect of Asphaltene on the Stability of Iraqi Water in Crude Oil Emulsions
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In the present work, asphaltenes and resins separated from emulsion samples collected from two Iraqi oil wells, Nafut Kana (Nk) and Basrah were used to study the emulsion stability. The effect of oil resins to asphaltene (R/A) ratio, pH of the aqueous phase, addition of paraffinic solvent (n-heptane), aromatic solvent (toluene), and blend of both (heptol) in various proportions on the stability of emulsions had been investigated. The conditions of experiments were specified as an agitation speed of 1000 rpm for 30 minutes, heating at 50 °C, and water content of 30%.  The results showed that as the R/A ratio increases, the emulsion will be unstable and the amount of water separated from emulsion increases. It was noticed that the em

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Publication Date
Sun Mar 05 2017
Journal Name
Baghdad Science Journal
Spectrophotometric Determination of Bisacodyl in Pure and Pharmaceutical Preparation via Oxidative Coupling Organic Reaction
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A simple, accurate and sensitive spectrophotometric way is used to determine Bisacodyl in pure and pharmaceutical preparations. The proposed method depends on using 2,4-Dinitrophenylhydrazine as chromogenic reagent . The method was based on the oxidative coupling reaction of Bisacodyl with 2,4-Dinitrophenylhydrazine with Sodium periodate in the presence of sodium hydroxide as alkaline media to form red water soluble dye product , that has a maximum absorption at ?max 522nm . Beer ,s law is obeyed in the concentration of (2.00–20.00) ?g.ml -1 .The molar absorptivity is (6505) L.mol-1.cm-1,a sandall sensitivity of(0.0555) ?g.cm-2), correlation coefficient of (0.9970) , Limitof detection (LOD) (0.0312 ?g.ml-1), limit of Quantitation (LOQ) (

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Publication Date
Sat May 01 2021
Journal Name
Proceedings Of The Thermal And Fluids Engineering Summer Conference
HEAT TRANSFER ENHANCEMENT IN PCM THERMAL ENERGY STORAGE VIA THE TRIPLEX TUBE HEAT EXCHANGER
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Publication Date
Fri Mar 01 2019
Journal Name
Journal Of Global Pharma Technology
Simultaneous Determination of Furosemide, Carbamazepine, Diazepam and Carvedilol in Quaternary Mixture via Derivative Spectrophotometry
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Quick and accurate quaternary mixture resolution of furosemide (FURO), carbamazepine (CARB), diazepam (DIAZ) and carvedilol (CARV) by using derivative spectrophotometric method was performed. FURO and CARV were determined by means of first (D1), second (D2), third (D3) and fourth (D4) derivative spectrophotometric methods, CARB was determined by using D1, D2, D3 derivatives, while D1 and D2 were used for the determination of DIAZ. The recommended methods were verified using laboratory prepared mixtures and then successfully applied for the pharmaceutical formulations analysis of the cited drugs. The results obtained revealed the efficiency of the proposed methods as quantitative tool of analysis of the quaternary mixture with no requirement

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Publication Date
Fri Jun 01 2018
Journal Name
Materials Science-poland
Thermal and electrical properties of polyimide/PANI nanofiber composites prepared via in situ polymerization
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Abstract<p> Polyimide/polyaniline nanofiber composites were prepared by in situ polymerization with various weight percentages of polyaniline (PANI) nanofibers. X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR), proved the successful preparation of PANI nanofiber composite films. In addition, thermal stability of PI/PANI nanofiber composites was superior relative to PI, having 10 % gravimetric loss in the range of 623 °C to 671 °C and glass transition temperature of 289 °C to 297 °C. Furthermore, the values of the loss tangent tanδ and AC conductivity σAC of the nanocomposite films were notably higher than those of pure polyimide. The addition of 5 wt.% to 15 wt.% PANI</p> ... Show More
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Publication Date
Thu Dec 31 2015
Journal Name
Kerbala Journal Of Pharmaceutical Sciences
Investigation the Factors Affecting on Gatifloxacin Eye Drop Stability
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This research included the study of different factors that may effect on gatifloxacin stability (anew quinolone synthetic antibacterial agent) in its aqueous solution in order to develop and optimize the best delivary of the drug to the eye (as eye drop) with maximum local concentration and minimum systemic absorption and toxicity.Different formulas of gatifloxacin solution for ophthalmic use (0.3%)w/v were prepared in citrate, acetate,citrate/phosphate and phosphate buffers,their tonicity adjusted with suitable quantity of sodium chloride.The effect of different factors that might affectthe stability of gatifloxacin in its prepared ophthalmic solution was studied and determined spectrophotometrically at 287 nm. The results showed t

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Publication Date
Sun Dec 02 2012
Journal Name
Baghdad Science Journal
Stability of Back Propagation Training Algorithm for Neural Networks
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In this paper, we derive and prove the stability bounds of the momentum coefficient µ and the learning rate ? of the back propagation updating rule in Artificial Neural Networks .The theoretical upper bound of learning rate ? is derived and its practical approximation is obtained

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Publication Date
Mon Jan 02 2017
Journal Name
Journal Of Educational And Psychological Researches
The emotional stability development, Ages 11 to 14 Years
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The current research aims to identify 1) the differences of emotional stability development level according to the variable of age; and 2) the differences of emotional stability development level according to the variable of gender (male, female). This study employed a descriptive approach, whereby a total of 165 primary and secondary school student was randomly selected from the directorate of AL -rusafa side (1st rusafa) of Baghdad province to constitute the sample of the study. The questionnaire was created based on the previous testes and studies that are relevant to emotional stability, and all its psychometrics features were examined. The researcher analyzed the data using SPSS statistic

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Publication Date
Fri Mar 28 2003
Journal Name
Journal Of Engineering
STABILITY OF UNREINFORCED AND REINFORCED EMBANKMENTS ON SOFT SOILS
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Publication Date
Tue Jul 30 2024
Journal Name
Academia Open
Positioning Preterm Newborns for Cardiorespiratory Stability A Global Insight
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