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6RZiZ4cBVTCNdQwCiUny
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
Sun Sep 30 2001
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Determination of Corrosion Parameters for a Cathodic Reaction Complicated by IR Drop Effect in a Flow System
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Publication Date
Mon Sep 25 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Determination and measuring some of the physical and chemical parameters in the clay of Lake Hamrin, Iraq
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The composition of the clay taken from the lake of Hamrin, Iraq was studied with the determination of the concentrations of the major oxides and the minor oxides in it.   Kaolinite was the most dominant clay in the samples, while quartz was the most abundant non-clay mineral. 

Some physico-chemical parameters in lake's water were determined such as oxygen, a chlorosity, nutrient salts,  pH, total alkalinity, total nitrogen, total phosphorous and silicate.

The effect of increased wastewater and human activities affected the composition of water and lead to a decrease in the productivity of the lake which was reflected by the relatively low pH values (average 8.0) and alkalinity in water as a result of t

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Publication Date
Sun Jun 11 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Spectrophotometric Determination of Tetracycline Hydrochloride in Pure Form and Pharmaceutical Preparation by Coupling with Diazotized Anthranilic Acid
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  A simple, fast and sensitive spectrophotometric method has been applied for the determination of tetracycline hydrochloride in its pure form and in pharmaceutical preparations. The method based on coupling reaction of the antibiotic with diazotized anthranilic acid to form a stable yellow azo dye which shows a maximum absorption at 419 nm. Uni- and multivariate approaches were followed in optimizing the experimental conditions. Under optimum experimental conditions obtained via multivariate (Central Composite Design), the linearity of the constructed calibration curve was in the range of 0.560 μg.mL-1 with molar absorptivity of 14619 L.mol-1.cm-1 and the value of detection limit was 0.2813μg.mL-1. The capability of the metho

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Publication Date
Sun Mar 02 2008
Journal Name
Baghdad Science Journal
Determination Of Micro Amount Of Spironolactone In Some Of Pharmaceutical Preparate By Using a Molecular Luminescence Technique.
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The present study include a new developed method of analysis for determination of drug Spironolaction (SP) in some Pharmaceuticals by Spectrofluorometric method. Spironolaction was determined under optimal experimental condition that follows :- The excitation spectrum was (l=351 nm), the emmetion spectrum was (l=518 nm), pH=1, the suitable temperature for reaction 60oC and the optimal time less than (3) minute. The analysis and rang statistical data was:-Linear dynamic rang (1-10) ?g.ml-1, the detection limit (D.L = 0.023 ?g.ml-1), Molar absorptivity (? = 29875 liter mole-1 cm-1), Relative standard deviation (%RSD = 0.78), (%Erel = 3.3) and recovery (Rec = 96.6) percentage. Determination of Spironolactone was accomplished by two methods

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Publication Date
Mon Jul 01 2019
Journal Name
Biocatalysis And Agricultural Biotechnology
Determination of Diazinon in fruit samples using electrochemical sensor based on carbon nanotubes modified carbon paste electrode
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Publication Date
Sat Jan 01 2022
Journal Name
Chemical Methodologies
Determination of the Quantity of Losartan Active Ingredient in the Medication Formulations via Turbidimetric-Flow Injection Technique
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Publication Date
Thu Dec 22 2022
Journal Name
Chemistry &amp; Chemical Technology
Turbidimetric Determination of Mebeverine Hydrochloride in Pharmaceutical Formulations Using Two Consecutive Detection Zones under Continuous Flow Conditions
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A simple, low cost and rapid flow injection turbidimetric method was developed and validated for mebeverine hydrochloride (MBH) determination in pharmaceutical preparations. The developed method is based on forming of a white, turbid ion-pair product as a result of a reaction between the MBH and sodium persulfate in a closed flow injection system where the sodium persulfate is used as precipitation reagent. The turbidity of the formed complex was measured at the detection angle of 180° (attenuated detection) using NAG dual&Solo (0-180°) detector which contained dual detections zones (i.e., measuring cells 1 & 2). The increase in the turbidity of the complex was directly proportional to the increase of the MBH concentration

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Publication Date
Thu Jun 01 2023
Journal Name
Baghdad Science Journal
Simultaneous Determination of Piroxicam and Codeine Phosphate Hemihydrate in a Pharmaceutical Dosage Form Using Validated HPLC Method
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An easy, eclectic, precise high-Performance Liquid Chromatographic (HPLC) procedure was evolved and validated to estimate of Piroxicam and Codeine phosphate. Chromatographic demarcation was accomplished on a C18 column [Use BDS Hypersil C18, 5μ, 150 x 4.6 mm] using a mobile phase of methanol: phosphate buffer (60:40, v/v, pH=2.3), the flow rate was 1.1 mL/min, UV detection was at 214 nm. System Suitability tests (SSTs) are typically performed to assess the suitability and effectiveness of the entire chromatography system. The retention time for Piroxicam was found to be 3.95 minutes and 1.46 minutes for Codeine phosphate. The evolved method has been validated through precision, limit of quantitation, specificity,

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Publication Date
Sun Jul 01 2012
Journal Name
Food Chemistry
High performance liquid chromatographic determination of aflatoxins in chilli, peanut and rice using silica based monolithic column
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A simple and rapid high performance liquid chromatographic with fluorescence detection method for the determination of the aflatoxin B1, B2, G1 and G2 in peanuts, rice and chilli was developed. The sample was extracted using acetonitrile:water (90:10, v/v%) and then purified by using ISOLUTE multimode solid phase extraction. After the pre-column derivatisation, the analytes were separated within 3.7 min using Chromolith performance RP-18e (100–4.6 mm) monolithic column. To assess the possible effects of endogenous components in the food items, matrix-matched calibration was used for the quantification and validation. The recoveries of aflatoxins that were spiked into food samples were 86.38–104.5% and RSDs were <4.4%. The method was

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Publication Date
Sun Mar 03 2019
Journal Name
Iraqi Journal Of Physics
Experimental observation of the far field diffraction patterns of functionalization single and multi-walled carbon nanotubes using nonlinear diffraction technique
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Nonlinear diffraction pattern can be induced by focusing CW
laser into a thin quartzes cuvette containing nanofluid. The number
of revealed pattern rings indicates to the nonlinear behavior of fluid.
Here, the nonlinear refractive index of each of functionalized single
wall carbon nanotube (F-SWCNTs) suspention and multi wall carbon
nanotube (F-MWCNTs) suspention have been investigated
experimentally .Each of CNTs suspention was at volume fraction of
13×10−5 and 6×10−5. Moreover the laser source at wavelength of
473 nm was used. The results show that SWCNTs suspention
possesses higher nonlinearty than other at the same volume fraction

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