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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
Thu Dec 01 2022
Journal Name
Baghdad Science Journal
Simultaneous Ratio Derivative Spectrophotometric Determination of Paracetamol, Caffeine and Ibuprofen in Their Ternary Form
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A new, accurate, precise and economic two spectrophotometric methods for determination of Paracetamol (Par), Ibuprofen (Ibu), and Caffeine (Caf) were suggested. Those methods were the first and second ratio derivative spectrum using a double devisor. Par, Ibu, and Caf showed many useful peaks for their quantified determination. The validity of all analysis modes for determination of the three compounds, peak to baseline, peak area and peak to peak were according to ICH. The linearity of two methods was between 5 µg/ml as a lower concentration and 50 µg/ml as the highest concentration for three compounds. Recovery percentage was around 100% and relative standard deviation was less than 2.6%. The methods were applied successfully in the

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Publication Date
Sun Jun 05 2016
Journal Name
Baghdad Science Journal
Development of Green Method for Trace Determination of Bendiocarb in Real Samples Using Emerson
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In this study, cloud point extraction combined with molecular spectrometry as an eco-friendly method is used for extraction, enrichment and determination of bendiocarb (BC) insecticide in different complex matrices. The method involved an alkaline hydrolysis of BC followed Emerson reaction in which the resultant phenol is reacted with 4-aminoantipyrene(4-AAP) in the presence of an alkaline oxidant of potassium ferric cyanide to form red colored product which then extracted into micelles of Triton X-114 as a mediated extractant at room temperature. The extracted product in cloud point layer is separated from the aqueous layer by centrifugation for 20 min and dissolved in a minimum amount of a mixture ethanol: water (1:1) followed

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Publication Date
Thu Dec 21 2017
Journal Name
International Journal Of Engineering &amp; Technology
Determination of liquefaction potential for two selected sites in Kerbala city- middle of Iraq
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Geotechnical characterization of the sites has been investigated with the collection of borehole data from different sources. Using the data, grain size distribution curves have been developed to understand the particle size distribution of the alluvium present. These curves were further used for preliminary assessment of liquefiable areas. From geotechnical characterization, it has been observed that the soil profile in the two sites is dominated by sand and silty sand.Seed and Idriss (1971) approachhas been usedevaluatethe liquefaction potentialbydeterminationof the relation between the maximum ground acceleration (a max/g) valuesdue to an earthquake and the relative density of a sand deposit in the field. The results reveal that

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Publication Date
Sun Dec 07 2008
Journal Name
Baghdad Science Journal
Spectrophotometric micro determination of drug promethazine hydrochloride in some pharmaceutical by chelating with Rhodium
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The drug promethazine hydrochloride (PRZH) forms with rhodium (II) a colored chelate (?max = 472 nm) complex at (pH = 2.1) which is extractable with benzyl alcohol as organic solvent. Under the appropriate experimental conditions a calibration plot was set up from which some analytical parameter were derived and deduced by regression. Standard addition procedure was also adopted. It has been estimated that the concentration of the drug PRZH to be 24.89 mg per unit and 24.19 mg per unit for both calibrations. Under optimal conditions, the developed method has been achieved the following characteristics: LDR (30 – 150 µg ml-1 ) PRZH , RSD % ( 0.6 – 2.47 ) , sandell sensitivity( 0.0844 µg. cm -2 ) , LOD ( 1.66 µgml-1 ) , recovery

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Publication Date
Fri Aug 30 2024
Journal Name
Iraqi Journal Of Science
The Dissipation of the Kinetic Energy for 2D Bounded Flow by Using Moment-Based Boundary Conditions with Burnett Order Stress for LBM
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     In this article, the lattice Boltzmann method with two relaxation time  (TRT)  for the  D2Q9 model is used to investigate numerical results for 2D flow. The problem is performed to show the dissipation of the kinetic energy rate and its relationship with the enstrophy growth for 2D dipole wall collision. The investigation is carried out for normal collision and oblique incidents at an angle of . We prove the accuracy of moment -based boundary conditions with slip and Navier-Maxwell slip conditions to simulate this flow. These conditions are under the effect of Burnett-order stress conditions that are consistent with the discrete Boltzmann equation. Stable results are found by using this kind of boundary condition where d

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Publication Date
Sun Jul 01 2012
Journal Name
International Journal Of Computer Mathematics
Numerical solution of the two-dimensional Helmholtz equation with variable coefficients by the radial integration boundary integral and integro-differential equation methods
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Publication Date
Wed Dec 03 2014
Journal Name
Ibn Al-haitham J.for Pure &appl.sci
Spectrophotometric Determination of Chlorpromazine – HCl Using Potassium Permanganate
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Twosimple, sensitive,accurate, and precise spectrophotometric methods have been developed for the determination of chlorpromazine – HCl in pure form and pharmaceutical formulation. The first method involved treatment of cited drug with a measured excess of permanganate in acid medium and the unreacted oxidant was measured at 525 nm. The second method involves the reaction of the drug with potassium permanganate in the presence of sodium hydroxide to produce a bluish – green colored manganite which is measurable at 610nm. All the experimental variables affecting the development of the manganite ions were investigatedand conditions were optimized. Working linearity ranges were 5-45 µg.mL-1and 1-20 µg.mL-1 by two methods respectively. Th

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Publication Date
Mon Mar 08 2021
Journal Name
Baghdad Science Journal
Flow injection- Spectrophotometric determination of some catecholamine drugs
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A new spectrophotometric flow injection method has been establish for the determintaions of some catecholaminedrugs

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Publication Date
Thu Jun 25 2020
Journal Name
International Journal Of Drug Delivery Technology
Development of a Simple Colorimetric Determination of Dexamethasone
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A simple, environmentally benign, cost-effective, and sensitive colorimetric determination for the pharmaceutical drug dexamethasone sodium phosphate (DXP) has been developed by the formation of a colored complex with fluoranil. The process was sensitive and linear over the range 1 to 40 μg/mL, excellent correlation coefficient 0.9989, recovery% 99.80 ± 1.3, limit of detection (LOD) and limit of quantification (LOQ) were 0.23 and 0.9 μg/mL, respectively, and good RSD ~1.63%. The experimental conditions were optimized after an intensive study. The approach was validated statistically for the quantification of the analyte in its pure and/or pharmaceutical form. Despite the proposed approach is selective, it still can be applied for

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Publication Date
Mon Feb 17 2020
Journal Name
Journal Of University Of Duhok
DETERMINATION OF ANTIOXIDANT ACTIVITY FOR METAL IONS COMPLEXES
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The synthesis and characterization of Schiff base and the complexities of metal ions and the evaluation of its antioxidant activities against 1.1-Diphenyl-2-picrylhydrazyl (DPPH) will compared with standard natural antioxidants and ascorbic acid. These prepared materials gave results are due exhibit excellent radical scavenging activities for all complexes with new prepared from reaction Schiff base and metal ions for [ Mn(II), Zn (II), Cd(II), Pd(II) and Hg(II) ]. The complexes prepared characterization by spectral methods (ultraviolet visible, infrared and mass spectra) will be identified in addition to the element micro analysis, (F.A.A.), magnetic sensitivity. The molar conductance values indicated that the complexes derived from Mn(II)

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