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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
Sat Oct 01 2016
Journal Name
International Communications In Heat And Mass Transfer
Study of synthesis, stability and thermo-physical properties of graphene nanoplatelet/platinum hybrid nanofluid
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In the present study a new synthesis method has been introduced for the decoration of platinum(Pt) on the functionalized graphene nanoplatelet (GNP) and also highlighted the preparation method of nanofluids. GNP–Pt uniform nanocomposite was produced from a simple chemical reaction procedure, which included acid treatment for functionalization of GNP. The surface characterization was performed by various techniques such as XRD, FESEMand TEM. The effective thermal conductivity, density, viscosity, specific heat capacity and stability of functionalized GNP–Pt water based nanofluids were investigated in different instruments. The GNP–Pt hybrid nanofluids were prepared by dispersing the nanocomposite in base fluid without adding any surfac

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Publication Date
Fri Oct 07 2022
Journal Name
Himalayan Economics And Business Management
Analyzing and Measuring the Relationship between Monetary Policy and Monetary Stability in the Iraqi Economy for the Period 1990-2020
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Monetary policy occupies a prominent role in achieving monetary stability by adjusting the growth rates of the number of available means of payment in line with changes in the size of the gross domestic product in the country and expressed by the monetary stability coefficient agreed upon by the International Monetary Fund, a term that hides the fact that there is a rate of change in the volume of commodity or real production which expresses the levels of aggregate supply in the economy, which corresponds to the quantities of cash in circulation, which represent a net purchasing power and stimulate aggregate demand, which completes the picture of the existence of the market mechanism, expressed by the monetary or economic stability

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Publication Date
Fri Jun 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
The Effect of the Stability of Some Commodity Activities in Iraq on the Estimation of the Statistical Data Models for the Period (1988-2000)
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There is an assumption implicit but fundamental theory behind the decline by the time series used in the estimate, namely that the time series has a sleep feature Stationary or the language of Engle Gernger chains are integrated level zero, which indicated by I (0). It is well known, for example, tables of t-statistic is designed primarily to deal with the results of the regression that uses static strings. This assumption has been previously treated as an axiom the mid-seventies, where researchers are conducting studies of applied without taking into account the properties of time series used prior to the assessment, was to accept the results of these tests Bmanueh and delivery capabilities based on the applicability of the theo

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Publication Date
Sun Oct 01 2023
Journal Name
Baghdad Science Journal
The Influence of Ablation Speed on the Synthesis of Carbon Nanostructures Via Pulsed Laser Ablation of Asphalt in Ethanol
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Pulsed liquid laser ablation is considered a green method for the synthesis of nanostructures because there are no byproducts formed after the ablation. In this paper, a fiber laser of wavelength 1.064 µm, peak power of 1 mJ, pulse duration of 120 ns, and repetition rate of 20 kHz, was used to produce carbon nanostructures including carbon nanospheres and carbon nanorods from the ablation of asphalt in ethanol at ablation speeds of (100, 75, 50, 10 mm/s).  The morphology, composition and optical properties of the synthesized samples were studied experimentally using FESEM, HRTEM, EDS, and UV-vis spectrophotometer. Results showed that the band gap energy decreased with decreasing the ablation speed (increasing the ablation time), the mi

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Publication Date
Thu Dec 21 2023
Journal Name
Mathematical Modelling Of Engineering Problems
Recovering Time-Dependent Coefficients in a Two-Dimensional Parabolic Equation Using Nonlocal Overspecified Conditions via ADE Finite Difference Schemes
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Publication Date
Sat Jan 01 2022
Journal Name
Journal Of Energy Storage
Intensifying the thermal response of PCM via fin-assisted foam strips in the shell-and-tube heat storage system
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Publication Date
Wed Jan 10 2018
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
ENCAPSULATION OF OMEGA-3 FATTY ACID USING NANOTECHNOLOGY TO IMPROVE ITS THERMAL STABILITY AND USE IT TO ENRICHING THE YOGURT: ENCAPSULATION OF OMEGA-3 FATTY ACID USING NANOTECHNOLOGY TO IMPROVE ITS THERMAL STABILITY AND USE IT TO ENRICHING THE YOGURT
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Concentrations 25, 50 and 100 mg of nano-capsules linolenic acid and non-capsulated fatty acid for 1kg of Milk was used for yogurt manufacture. The results showed no significant differences in the ratio of titration acidity and pH values between all processed treatments at the beginning and during of period storage. The treatments was added to it coated omega-3 by nano method were the least exposed to the oxidation process from the non-capsules omega-3, And for shield of The poly lactic acid had a significant role in the protection of alpha-linolenic acid against lipolysis by the formation of a protective layer to protect the acid from the activity of lipases enzymes, and the addition of fatty acid linolenic to milk was determined the gr

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Publication Date
Thu Apr 25 2019
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
BIOLOGICAL ACTIVITY OF THE CAROTENOIDS WHICH ARE PRODUCED FROM LOCAL ISOLATE Rhodotorula mucilaginosa AND DETRERMINATION THE CONDITIONS AFFECTING THEIR STABILITY: BIOLOGICAL ACTIVITY OF THE CAROTENOIDS WHICH ARE PRODUCED FROM LOCAL ISOLATE Rhodotorula mucilaginosa AND DETRERMINATION THE CONDITIONS AFFECTING THEIR STABILITY
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Biological activity of the carotenoids which are produced fromchemically-mutaed local isolate of Rhodotorula mucilaginosawas studied. The results showed variation of inhibition activity of caritenoids against different types of pathogenic bacteria include, Staph aureus, E. coli, B. subtilis and Salmo. typh., the number declined from 2×107cell/ml to 2×104, 5×104, 2×105, 9×105 cell/ml respectively after 24hour. The produced carotenoids from alocal mutant Rhodotorula mucilaginosa revealed an antioxidant activity as free radical removal of 85.6%. Carotinoides revealed a highest stability in petroleum ether solvent for 30 days at room temperature. It found that the pigment was more stability in sesame oil compared with sun flower and coc

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Publication Date
Sun May 01 2016
Journal Name
Journal Of Engineering
Production of Methyl Ester (Biodiesel) from Used Cooking Oils via Trans-esterification process
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Used cooking oil was undergoing trans-esterification reaction to produce biodiesel fuel. Method of production consisted of pretreatment steps, trans-esterification, separation, washing and drying. Trans-esterification of treated oils was studied at different operation conditions, the methanol to oil mole ratio were 6:1, 8:1, 10:1, and 12:1, at different temperature 30, 40, 50, and 60 º C, reaction time 40, 60, 80, and 120 minutes, amount of catalyst 0.5, 1, 1.5, and 2 wt.% based on oil and mixing speed 400 rpm. The maximum yield of biodiesel was 91.68 wt.% for treated oils obtained by trans-esterification reaction with 10:1 methanol to oil mole ratio, 60 º C reaction temperature, 80 minute reactio

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Publication Date
Thu Aug 31 2017
Journal Name
Journal Of Engineering
Enhanced Performance of Consensus Wireless Sensor Controlled System via Particle Swarm Optimization Algorithm
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     This paper describes the application of consensus optimization for Wireless Sensor Network (WSN) system. Consensus algorithm is usually conducted within a certain number of iterations for a given graph topology. Nevertheless, the best Number of Iterations (NOI) to reach consensus is varied in accordance with any change in number of nodes or other parameters of . graph topology. As a result, a time consuming trial and error procedure will necessary be applied
to obtain best NOI. The implementation of an intellig ent optimization can effectively help to get the optimal NOI. The performance of the consensus algorithm has considerably been improved by the inclusion of Particle Swarm Optimization (PSO). As a case s

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