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
The concentration of elements were analyzed of twelve cultivation medium (Peat moss, Perlite and Hermon) selected from Iraqi markets using X-ray fluorescence techniques. The analytical results show that the cultivation medium contained high concentration of (Na, Al, Si, S, K, Ca, Fe) and low concentration of (Mg, P, Cl, Ti, V, Cr, Mn, Co, Ni, Cu, Zn). The samples also contained trace concentration of (Ge, As, Se, Br, Sr, Y, Mo, Cd, I, Hg, Pb, U). The results were compared using atomic absorption spectrophotometric technique for measuring the concentration of (K, Ca, Cu, Mn, Zn, Pb).
The Results showed that there is significant difference in the concentration of each element in most of the samples. The concentrations of elements a
... Show MoreSpectrophotometric method was developed for the determination of copper(II) ion. Synthesized (2,2[O-Tolidine-4,4-bis azo]bis[4,5-diphenyl imidazole]) (MBBAI) was used as chromogenic reagent at pH=5. Various factors affecting complex formation, such as, pH effect, reagent concentration, time effect and temperature effect, have been considered and studied. Under optimum conditions concentration ranged from (5.00-80.00) µg/mL of copper(II) obeyed Beer`s Low. Maximum absorption of the complex was 409nm with molar absorpitivity 0.127x104 L mol-1 cm-1. Limit of detection(LOD) and Limit of quantification were 1.924 and 6.42 μg/mL, respectively.
... Show MoreA new simple and sensitive spectrophotometric method for the determination of trace amount of Cu(II) in the ethanol solution have been developed. The method is based on the complexation of Cu(II) with ethyl cyano(2-methyl carboxylate phenyl azo acetate) (ECA) in basic medium of sodium hydroxide givining maximum absorbance at (λmax = 521 nm). Beer's law is obeyed over the concentration range (5-50) (μg / ml) with molar absorptivity of (3.1773 × 102 L mol-1 cm-1) and correlation coefficient (0.9989). The optimum conditions for the determination of Cu(II)-complex and have been studied and applied to determine Cu(II) in synthetic water sample using simple and standard addition methods.
Epithelial ovarian cancer is the leading cause of cancer deaths in women. To date, an effective screening tool for ovarian cancer has not been identified Several clinical and biological factors including serum cancer antigen 125 (CA- 125) have been assessed for prognostic and predictive relevance CA-125 is an epithelial marker derived from coelomic epithelium. It is elevated in 90% of advanced ovarian cancers and in 50% of early ovarian cancers while 20% of ovarian cancers have low or no expression of CA- 125 CA-125 concentrations were measured by Mini Vidas test (VIDAS CA125 II / BIOMERIEUX / France). The median CA-125 levels were significantly higher in the sera of ovarian cancer patients than in those with benign tumors an
... Show MoreCo(II) ion was determined by a new, accurate, sensitive and rapid method via a
continuous flow injection analysis (CFIA) with a chemiluminescence reaction based on
the oxidation of Luminol which is loaded on poly acrylic acid gel beads by hydrogen
peroxide in presence of Cobalt (II) ion as a chemiluminescence catalyst. Chemical and
physical parameters were investigated to obtain the best conditions. Linear dynamic
range of Cobalt (II) ion was from 0.1-20.0 μg.ml-1 with a correlation coefficient r =
0.9758, limit of detection (L.O.D) 0.2 ng/sample from the step wise dilution of lowest
concentration in the calibration graph with the percentage relative standard deviation for
3 μg.ml-1 Co(ll) solution is 0.8537% (n
A simple, rapid and environmentally friendly dispersive liquid–liquid microextraction method-based spectrophotometric method for the trace determination of folic acid has been developed. The proposed method is based on the formation of a deep yellow product via reaction of folic acid and 1,2-naphthoquine-4-sulfonate at pH = 9. The formed complex was extracted using a mixture of chloroform and ethanol. Then, the tiny organic droplets were measured at λ = 520 nm. At the optimum conditions, linearity was ranged from 0.05 to 1.5 μg/mL for the standard and samples, with a linear correlation coefficient of 0.9996. The detection limits were 0.02, 0.027, 0.03, 0.02 and 0.04 μg/mL for standard, tablet (5 mg), tablet (1 mg), syrup and fl
... Show MoreThe new organic reagent 2-[Benzo thiazolyl azo]-4,5-diphenyl imidazole was prepared and used as complexing agent for separation and spectrophotometric determination of Cu2+ ion in some samples include plants, soil, water and human blood serum. Initially determined all factors effect on extraction method and the results show optimum pH was (pHex=9), optimum concentration was 40?g/5mLCu2+ and optimum shaking time was (15min.), as well stoichiometry study appears the complex structure was 1:1 Cu2+: BTADPI. Interferences effect of cations were studied. Synergism effect shows MIBK gave increasing in distribution ratio (D). Organic solvent effect appears there is no any linear relation between dielectric constant for organic solvent used and dis
... Show MoreA new Turbidimetric method characterized by simplicity, accuracy and speed for determination of iron(III) in drug samples by continuous flow injection analysis. The method was based on the formation of complex for iron(III) with 8-hydroxyquinoline in presence of ammonium acetate as a medium for the formation of deep green precipitate and this precipitate was determined using homemade Linear Array Ayah-5SX1-T-1D continuous flow injection analyser. The optimum parameters were 2.6 mL.min-1 flow rate using H2O as a carrier, 1.9 mL.min-1 (14 mmol.L-1) ammonium acetate, 2.4 mL.min-1 (14 mmol.L-1) 8-hydroxyquinoline, 60 L sample volume and open valve for the purge of the sample segment. Data treatment shows that linear range 0.1-8.0 mmol.L-1
... Show MoreA newly developed analytical method characterized by its speed and sensitivity for the determination of metoclopramide hydrochloride (MCP-HCl) in pure and pharmaceutical preparation via turbidimetric measurement (0-180o) by Ayah 6SX1-T-2D Solar cell-CFI Analyser. The method was based on the reaction of phosphomolybdic acid with metoclopramide hydrochloride in acidic medium to form yellowish white precipitate for the ion-pair complex. Turbidity was measured via the reflection of incident light that collides on the surface precipitated particles at 0-180o. Chemical and physical parameters were studied and optimized. The calibration graph was linear in the range of 0.0005-3 or 0.0005- 4 mMol.L-1, with correlation coefficient r = 0.9947&
... Show MoreThe current work was undertaken to obtain the crude extract of PPO and laccase enzyme from the leaves of Malva parviflora. All leaves were washed with tap water, then the extraction was performed to acquire the crude extract’s enzymes. One gram of Malva parviflora leaves was homogenized in various volumes of distilled water (1:10, 1:5, and 1:2 w: v). The results showed that polyphenol oxidase and laccase with a ratio of 1:10 (w:v) gave the highest specific activity of 112.3 with 0.394 U/mg proteins. In addition, Malva parviflora leaves were homogenized with several types of buffers with two concentration (0.2 and 0.1 M) for PPO and laccase extraction. These buffers were potassium
... Show More