Preferred Language
Articles
/
alkej-156
Aircraft Lateral-Directional Stability in Critical Cases via Lyapunov Exponent Criterion
...Show More Authors

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 .

View Publication Preview PDF
Quick Preview PDF
Publication Date
Mon Jan 01 2024
Journal Name
Journal Of Oral Medicine And Oral Surgery
Evaluating dental implant stability using three devices Osstell<sup>®</sup>, Periotest<sup>®</sup>, and AnyCheck<sup>®</sup>: a clinical study
...Show More Authors

Introduction: Implant stability is usually measured with resonance frequency analysis (RFA) and damping capacity assessment (DCA). This study aimed to measure primary and secondary stabilities using 3 devices that are based on these methods, namely; RFA (Osstell®) and DCA (Periotest® and AnyCheck®) to assess the correlations of the measurements obtained by these devices and the correlations between implant stability and insertion torque. Material and Methods: This observational prospective study included 35 dental implants. The implant stability was measured using the 3 devices. Mann–Whitney U

... Show More
View Publication
Crossref (2)
Scopus Crossref
Publication Date
Wed Oct 02 2024
Journal Name
International Development Planning Review
A COMPARATIVE STUDY OF THE AMOUNT OF FORCE EXERTED ON THE GROUND AND THE TIME OF PROPULSION IN THE VERTICAL AND HORIZONTAL JUMPING TESTS FROM STABILITY USING A FOOT SCAN DEVICE
...Show More Authors

Publication Date
Sat May 01 2021
Journal Name
Journal Of Physics: Conference Series
Violet Laser Irradiation Effect on The Optical Properties of Cobalt oxide (CoO<sub>2</sub>) Thin Films deposited via Semi-Computerized Spraying System
...Show More Authors
Abstract<p>The existing investigation explains the consequence of irradiation of violet laser on the optic properties of (CoO<sub>2</sub>) films. The film was equipped by the utilization of semi-computerized spray pyrolysis technique (SCSPT), it is the first time that this technique is used in the preparation and irradiation using a laser in this technique. From the XRD analysis, the crystalline existence with trigonal crystal system was when the received films were processed by continuous violet laser (405 nm) with power (1W) for different laser irradiation time using different number of times a laser scan (0, 6, 9, 12, 15 and 18 times) with total irradiation time(0,30,45,60,75,90 min</p> ... Show More
View Publication Preview PDF
Scopus Crossref
Publication Date
Sat Jun 21 2025
Journal Name
Journal Of University Of Anbar For Pure Science
Semi – automated analysis for the Nanoscale determination of Chlorpheniramine maleate drug using sodium nitroprusside by continuous flow feed via homemade NAG-SSP Photometer
...Show More Authors

This study presents a rapid, sensitive, and straightforward approach to measure chlorpheniramine maleate (CPM) by using turbidity CFIA. The method involves CPM reacting with sodium nitroprusside (Nitropress) to produce a pale white precipitate. The NAG-SSP-5S1D analyzer was used to measure turbidity at 0°–180° angle to detect the attenuation of incident light as a result of collision on the surfaces of the precipitate particles. The linear range of CPM measurements was between 0.008 and 11 m.mol/L, with correlation coefficient of 0.9983 and R2% = 99.65. The limit of detection was determined to be 0.0328 µg/sample from the lowest concentration in the calibration curve, and the repeatability of the method (RSD%) was less than 0.4% (n = 6

... Show More
View Publication
Scopus (1)
Scopus Crossref
Publication Date
Mon Feb 22 2021
Journal Name
Educatum Journal Of Science, Mathematics And Technology
Effect of ammonia/gallium ratio and growth temperature towards the surface morphology of semi-polar GaN grown on m-plane sapphire via MOCVD
...Show More Authors

A single-crystalline semi-polar gallium nitride (11-22) was grown on m-plane (10-10) sapphire substrate by metal organic chemical vapor deposition. Three-step approach was introduced to investigate the grain size evolution for semi-polar (11-22) GaN. Such approach was achieved due to the optimized gallium to ammonia ratio and temperature variations, which led to high quality (11-22) oriented gallium nitride epilayers. The full width at half maximum values along (-1-123) and (1-100) planes for the overgrowth temperature of 1080°C were found to be as low as 0.37° and 0.49°, respectively. This was an indication of the enhanced coalescence and reduction in root mean square roughness as seen by atomic force microscopy. Surface analysi

... Show More
View Publication Preview PDF
Crossref
Publication Date
Mon Jun 30 2014
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Experimental Determination of the Elastic and Viscous Behavior of Polycarbonate Melts at Different Temperatures and Their Relationship to the Steady State Viscosity via the Cox-Merz Rule
...Show More Authors

Rheological instrument is one of the basic analytical measurements for diagnosing the properties of polymers fluids to be used in any industry. In this research polycarbonate was chosen because of its importance in many areas and possesses several distinct properties.
Two kinds of rheometers devices were used at different range of temperatures from 220 ˚C-300 ˚C to characterize the rheological technique of melted polycarbonate (Makrolon 2805) by a combination of different investigating techniques. We compared the results of the linear (oscillatory) method with the non-linear (steady-state) method; the former method provided the storage and the loss modulus of melted polycarbonate, and presented the Cox-Merz model as well. One of the

... Show More
View Publication Preview PDF
Publication Date
Thu Dec 01 2022
Journal Name
Baghdad Science Journal
Synthesis, Spectral Identification, Antibacterial Evaluationand Theoretical Study of Co, Fe, Rh and Pd Complexes for 2-benzoylthiobenzimidazol
...Show More Authors

A new novel series of metalcomplexes are prepared from reactions between 2-benzoylthio- benzimidazole (L) with metal salts of Co (II) , Fe(III) and Rh (III) , while Pd(II) complex was obtained by mixing ligandsof 2-benzoylthiobenzimidazole (L) as primary ligand and bipyridine (L/)as secondary ligand as well as palladium chloride as metal salt in an ethanoic medium. The geometry of these compounds were identified using C.H.N.microanalysis, Ultraviolet–visible, Fourier transforms infrared, magnetic susceptibility, molar conductivity and flame atomic absorption (A.A). From the dataobtained by these spectral analyses, the molecular structures for Rh and Fe complexes were proposed to be octahedral geometry. A square planar const

... Show More
View Publication Preview PDF
Scopus (5)
Scopus Clarivate Crossref
Publication Date
Sun Oct 04 2020
Journal Name
وزارة التخطيط/الجهاز المركزي للتقييس والسيطرة النوعية
تحضير وتشخيص ودراسة نظرية وتجريبية لتثبيط تأكل سبيكة الفا- براص في ماء البحر ‏بفعل مثبط تأكل جديد مشتق من 2-امينوبينزوثايوزول
...Show More Authors

يهدف البحث إلى تحضير سلسلة من معقدات العناصر الانتقالية ثنائية التكافؤ(المنغنيز, الكوبلت, النيكل, الخارصين ‏والكادميوم) مع المركب الجديد(‏KL‏) والمشتق من تفاعل ثنائي كبريتيد الكاربون و المركب الوسطي (‏HD‏). شخصت ‏المعقدات ذات الصيغة العامة[‏M(L)2‎‏] بواسطة طيف الرنين النووي المغناطيسي البروتوني والكربوني للمركب الجديد ‏وقياسات الأشعة تحت الحمراء والطيف الإلكتروني ودرجات الانصهار و التوصيلية المولارية و ت

... Show More
Publication Date
Sun Oct 20 2024
Journal Name
Engineering Reports
A Theoretical and Experimental Investigation of the Effects of Inverted Wings Modifications on the Stability and Aerodynamic Performance of a Sedan Car at Cornering
...Show More Authors
ABSTRACT<p>This research examines the impact of cornering on the aerodynamic forces and stability of a Nissan Versa (Almera) passenger sedan car by introducing novel modifications. These modifications included single inverted wings with end plates as a front spoiler, double‐element inverted wings with end plates as a rear spoiler, and incorporating the ground as a diffuser under the car trunk. The goal is to enhance the performance and stability of conventional passenger cars. To ensure the accuracy of the numerical data, the study utilized multiple methodologies to model the turbulence model, ultimately selecting the most suitable option. This involved comparing numerical data with wind tunnel experimental d</p> ... Show More
View Publication
Scopus (1)
Crossref (1)
Scopus Clarivate Crossref
Publication Date
Sun May 01 2016
Journal Name
Journal Of Engineering
Prediction of Ryznar Stability Index for Treated Water of WTPs Located on Al-Karakh Side of Baghdad City using Artificial Neural Network (ANN) Technique
...Show More Authors

In this research an Artificial Neural Network (ANN) technique was applied for the prediction of Ryznar Index (RI) of the flowing water from WTPs in Al-Karakh side (left side) in Baghdad city for year 2013. Three models (ANN1, ANN2 and ANN3) have been developed and tested using data from Baghdad Mayoralty (Amanat Baghdad) including drinking water quality for the period 2004 to 2013. The results indicate that it is quite possible to use an artificial neural networks in predicting the stability index (RI) with a good degree of accuracy. Where ANN 2 model could be used to predict RI for the effluents from Al-Karakh, Al-Qadisiya and Al-Karama WTPs as the highest correlation coefficient were obtained 92.4, 82.9 and 79.1% respe

... Show More
View Publication Preview PDF