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Free Boundary Determination in Nonlinear Diffusion
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Abstract<p>Free boundary problems with nonlinear diffusion occur in various applications, such as solidification over a mould with dissimilar nonlinear thermal properties and saturated or unsaturated absorption in the soil beneath a pond. In this article, we consider a novel inverse problem where a free boundary is determined from the mass/energy specification in a well-posed one-dimensional nonlinear diffusion problem, and a stability estimate is established. The problem is recast as a nonlinear least-squares minimisation problem, which is solved numerically using the <italic>lsqnonlin</italic> routine from the MATLAB toolbox. Accurate and stable numerical solutions are achieved. For noisy data, instability is manifest in the derivative of the moving free surface, but not in the free surface itself nor in the concentration or temperature.</p>
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Publication Date
Tue Jun 01 2010
Journal Name
Journal Of Engineering 5263
COUPLED VERTICAL – TORSIONAL AND LATERAL FREE VIBRATION OF THIN-WALLED CURVED BEAM
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This study is concerned with the derivation of differential equation of motion for the free coupled vertical – torsional and lateral vibration of opened thin-walled curved beams. The curved beam to be considered in this study is of isotropic opened thin – walled (I) section with equal top and bottom flanges. The derivation depends on Hamilton's principle which required finding the potential and kinetic energy of the curved beam section due to internal stresses and all types of movements (Vertical,Torsional and Lateral) .The effect of restrained warping displacement is also considered in this study. Three differential equations are derived for vertical, torsional and lateral movement .and approximate solutions are developed by using the

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Publication Date
Sat Jul 22 2023
Journal Name
Journal Of Engineering
Effect of Steel Fibers on the Properties of Refractory Free Cement Concrete
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Free cement refractory concrete is a type of refractory concrete with replacing alumina cement by bonding materials such as white kaolin, red kaolin and fumed silica. The free cement refractory concrete used in many applications like Petrochemicals, iron furnaces and cement production industries. The research clarifies the effect of steel fibers with two types crimped steel fibers and hooked steel
fibers with percentages 0.5%, 1% and 1.5% by volume from weight of bauxite aggregates. The additions of steel fibers with two types gave good properties in high temperatures where the specimens keep the dimension without failure and the properties made the best. the percentage of increasing for thermal conductivity was 44% for 1.5% crimped

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Publication Date
Mon Jan 28 2013
Journal Name
Spie Proceedings
Enhancement of security for free space optics based on reconfigurable chaotic technique
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Free Space Optical (FSO) technology offers highly directional, high bandwidth communication channels. This technology can provide fiber-like data rate over short distances. In order to improve security associated with data transmission in FSO networks, a secure communication method based on chaotic technique is presented. In this paper, we have turned our focus on a specific class of piece wise linear one-dimensional chaotic maps. Simulation results indicate that this approach has the advantage of possessing excellent correlation property. In this paper we examine the security vulnerabilities of single FSO links and propose a solution to this problem by implementing the chaotic signal generator “reconfigurable tent map”. As synchronizat

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Publication Date
Mon May 20 2019
Journal Name
The Journal Of Engineering
Experimental comparison of two linear machines developed for the free piston engine
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: In this study, a linear synchronous machine is compared with a linear transverse flux machine. Both machines have been designed and built with the intention of being used as the power take off in a free piston engine. As both topologies are cylindrical, it is not possible to construct either using just flat laminations and so alternative methods are described and demonstrated. Despite the difference in topology and specification, the machines are compared on a common base in terms of rated force and suitability for use as a generator. Experience gained during the manufacture of two prototypes is described.

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Publication Date
Sun Sep 01 2013
Journal Name
Baghdad Science Journal
Antioxidant and free radical scavenging effects of Iraqi sumac ( Rhus coriaria L)
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This study was carried out to evaluate the antioxidant activity of Iraqi sumac seeds (Rhus coriaria. L) (Anacardiaceae). Total phenolic compounds and flavoniods were determined in three different sumac seed extracts (SSE) (aqueous,ethanolic and methanolic extract). For extraction Antioxidant activity of SSE were evaluated by various antioxidant assays, including total antioxidant capacity, reducing power,by using 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging, nitric oxide scavenging, Hydroxyl radical scavenging, and metal ion chelating activities. These various antioxidant activities were compared with ascorbic acid as a standard antioxidant.The results showed that the three(SSE), contained large amounts of phenolic and flavonio

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Publication Date
Tue Jun 30 2020
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
Determination of some heavy Metals in tattoo Stickers in Children sweets available in local markets: Determination of some heavy Metals in tattoo Stickers in Children sweets available in local markets
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The objective of this study is to determination the content of some heavy metals (lead, cadmium, chromium) in colored tattoo stickers. twelve kinds of colored tattoo stikcers were collected from Baghdad markets, it was estimated heavy metals using atomic absorption spectrophotometer (Shimadzu A5000). The results indicated the concentrations of lead in all samples (1.61_1.00 mg / kg) and chromium in the three samples (0.85_0.97 mg / kg) while other samples are free of chromium , and cadmium. These elements are the components of printing inks and dyes in tattoo stickers, and this does not conform to the health and safety conditions for the packaging of food according to the organizations of the health and safety of

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Publication Date
Tue Mar 01 2022
Journal Name
Materials Today Communications
Fe2O3-SiO2 nanocomposite film-induced high nonlinear effect for multiwavelength mode-locked generation in ytterbium-doped fiber laser
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In this work, the possibility of a multiwavelength mode-locked fiber laser generation based on Four-Wave Mixing (FWM) induced by Fe2O3-SiO2 nanocomposite material is investigated for the first time. A multiwavelength mode-locked pulses fiber laser are generated from Ytterbium–doped fiber laser (YDFL) due to the combined action of high nonlinear absorption and high refractive coefficients of Fe2O3-SiO2 nanocomposite incorporated inside YDFL ring cavity. Up to more than 20 lasing lines in the 1040–1070 nm band with an equally lines separation of ~0.6 nm have been observed by just simple variation of passive modulation of the state of the polarization and the pump power altogether. Moreover, a passively mode-locked operation of YDFL laser

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Publication Date
Tue Sep 17 2013
Journal Name
International Journal Of Engineering And Innovative Technology (ijeit)
Study of Optical Properties (Linear and Nonlinear) and Structures for CdS Thin Film Preparation in Spray Pyrolysis Technique
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Publication Date
Sun Sep 01 2013
Journal Name
Baghdad Science Journal
Spectrophotometric method for the determination of Captopril in pharmaceutical formulations
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A simple, rapid and sensitive spectrophotometric method has been developed for the determination of captopril in aqueous solution. The method is based on reaction of captopril with 2,3-dichloro 1,4- naphthoquinon(Dichlone) in neutral medium to form a stable yellow colored product which shows maximum absorption at 347 nm with molar absorptivity of 5.6 ×103 L.mole-1. cm-1. The proposed method is applied successfully for determination of captopril in commercial pharmaceutical tablets.

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Publication Date
Sun Jun 03 2012
Journal Name
Baghdad Science Journal
Spectrofluorimetric method for the determination of glibenclamide in pharmaceutical formulations
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A sensitive spectrofluorimetric method for the determination of glibenclamide in its tablet formulations has been proposed. The method is based on the dissolving of glibenclamide in absolute ethanol and measuring the native fluorescence at 354 nm after excitation at 302 nm. Beers law is obeyed in the concentration of 1.4 to 10 µg.ml-1 of glibenclamide with a limit of detection (LD) of 0.067 µg.ml-1 and a standard deviation of 0.614. The range percent recoveries (N=3) is 94 - 103.

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