881 research outputs found

    Numerical Treatment for Special Type of Mixed Linear Delay Volterra Integro-Differential Equations

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    The idea of research is a representation of the nonlinear pseudo-random generators using state-space equations that is not based on the usual description as shift register synthesis but in terms of matrices. Different types of nonlinear pseudo-random generators with their algorithms have been applied in order to investigate the output pseudo-random sequences. Moreover, two examples are given for conciliated the results of this representation

    Adsorption Study for Trifluralin on Iraqi ? –Alumina

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    Equilibrium adsorption isotherm for the removal of trifluralin from aqueous solutions using ? –alumina clay has been studied. The result shows that the isotherms were S3 according Giels classification. The effects of various experimental parameters such as contact time, adsorbent dosage, effect of pH and temperature of trifluralin on the adsorption capacities have been investigated. The adsorption isotherms were obtained by obeying freundlich adsorption isotherm with (R2 = 0.91249-0.8149). The thermodynamic parameters have been calculated by using the adsorption process at five different temperature, the values of ?H, ?G and ?S were (_1.0625) kj. mol-1, (7.628 - 7.831) kj.mol-1 and (_2.7966 - _2.9162) kg. k-1. mol-1 respectively. The kinetic study of adsorption process has been studied depending on three kinetic equations: 1- Allergen equation 2- Morris –weber eguation 3- Reichenberg eguation. In general, the result shows the isotherm were on ?- alumina according to Giels classification.? –alumina and thermodynami

    Interaction between Sulfur and Α-Tocopherol and Their Effects on Alleviating Selenium Toxicity in Mung Bean Cuttings and Seedlings

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    Physiologically, the sulphur (S) and α-tocopherol (α-T) role in alleviating selenium (Se) toxicity has been studied by using Hoagland solution as balanced environment for S and Se content in mung bean cuttings & seedlings. However, toxic selenium level at optimum promontory concentrations of both S and α-T were supplied to seedlings and cuttings of mung bean as experimental system, which taken from 10-day-old light grown seedlings under standard conditions. The results indicated the following: Raising of Se level in cutting and seedling parts (roots, hypocotyls, epicotyl and leaves) significantly, when Se was supplied individually. Significant decline in Se-uptake and accumulation in plant tissues ,when supplied with S whereas, α-T had no effect on uptake that encouraging its translocation & accumulation in leaves .There after it causes , diminishing its conc. in hypocotyls and epicotyls . Consequently,  Se level was  declined in hypocotyls in both cases when S and α-T supplied individually  whereas, the situation was different when supplied together with Se , in terms of S & Se content. The mechanism of Se-tolerance in seedlings of mung bean is reside in roots, that causes its accumulation and sequestration in seedling roots at high level coincided with low amount acropetally translocated, leaves (in case of using mung bean seedlings instead of cuttings). Keywords: detoxification, mung bean cuttings, rooting response, selenium, sulfur, and α-   tocopherol

    Some statistical methods for dimension reduction

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    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityThe aim of the work in this thesis is to carry out dimension reduction (DR) for high dimensional (HD) data by using statistical methods for variable selection, feature extraction and a combination of the two. In Chapter 2, the DR is carried out through robust feature extraction. Robust canonical correlation (RCCA) methods have been proposed. In the correlation matrix of canonical correlation analysis (CCA), we suggest that the Pearson correlation should be substituted by robust correlation measures in order to obtain robust correlation matrices. These matrices have been employed for producing RCCA. Moreover, the classical covariance matrix has been substituted by robust estimators for multivariate location and dispersion in order to get RCCA. In Chapter 3 and 4, the DR is carried out by combining the ideas of variable selection using regularisation methods with feature extraction, through the minimum average variance estimator (MAVE) and single index quantile regression (SIQ) methods, respectively. In particular, we extend the sparse MAVE (SMAVE) reported in (Wang and Yin, 2008) by combining the MAVE loss function with different regularisation penalties in Chapter 3. An extension of the SIQ of Wu et al. (2010) by considering different regularisation penalties is proposed in Chapter 4. In Chapter 5, the DR is done through variable selection under Bayesian framework. A flexible Bayesian framework for regularisation in quantile regression (QR) model has been proposed. This work is different from Bayesian Lasso quantile regression (BLQR), employing the asymmetric Laplace error distribution (ALD). The error distribution is assumed to be an infinite mixture of Gaussian (IMG) densities

    Isolation, characterization and quantification of a pentacyclic triterpinoid compound ursolic acid in Scabiosa palaestina L. distributed in the north of Iraq

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    Ursolic acid (UA, 3 ?-hydroxy-urs-12-en-28-oic acid) are isomeric triterpenic acids. The high quantities of pentacyclic triterpenoids in Scabiosa species seems to be obvious and there is an evidence that most of pentacyclic triterpenoids that have been isolated are saponins. This is one of the most important characteristic of the genus Scabiosa, the main aglycones are ursolic acid and oleanolic acid. In the current study, isolation from the aerial part and roots of Scabiosa palaestina L. was performed using Preparative HPLC. Furthermore, detection and quantitation of ursolic acid was performed by high performance thin layer chromatography (HPTLC). The identification of isolated triterpenoid involves two methods including FT-IR coupled with LC-MS/MS that have been used for the simultaneous determination of the isolated UA. Quantitative analysis of Ursolic acid content in chloroform fractions revealed that both of the aerial parts and roots contain comparable concentration of 0.052 and 0.054 mg/ml respectively. The FT-IR and LC-MS/MS spectra of the isolated compound shows good agreement with those reported in literatures of Ursolic acid. Quantitative concentration of UA in chloroform fraction revealed that aerial parts and roots contain comparable concentrations and the spectral data for the isolated unknown were in good agreement with those reported in literature of UA

    PHYTOCHEMICAL INVESTIGATION OF LEAVES AND SEEDS OF CORCHORUS OLITORIUS L. CULTIVATED IN IRAQ

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    Objective: The aim of this study was to investigate chemical constituents of leaves and seeds of Corchorus olitorius since no phytochemical investigation had been done previously in Iraq.Methods: Leaves and seeds of C. olitorius were defatted by maceration in hexane for 24 h. The defatted plant materials were extracted using Soxhlet apparatus, the aqueous methanol 85% as a solvent extraction for 24 h, and fractionated by petroleum ether, chloroform, ethyl acetate, and n-butanol. The ethyl acetate, n-butanol, and n-butanol after hydrolysis fractions for each part (leaves and seeds) were analyzed by high-performance liquid chromatography (HPLC) and high-performance thin-layer chromatography (HPTLC) for its phenolic acid and flavonoid contents. The petroleum ether fraction from the leaves was analyzed using Gas chromatography/mass spectrometer (GC/MS). Flavonoids and phenolic acid derivative were isolated from the ethyl acetate of leaf fraction and n-butanol after hydrolysis fraction of the seeds and identified by mass spectrometry, infrared, HPLC, and HPTLC.Results: The different chromatographic and spectroscopic results revealed the presence of luteolin, quercetin, astragalin, isoquercetin, catechins, and 3,5-dicaffeoylquinic acid (3,5-DCQA) in both leaves and seeds of C. olitorius and also 17-octadecynoic acid, 9-octadecanoic acid (oleic acid), hexadecenoic acid (palmitic acid), 9,12-octadecanoic acid (linoleic acid), octadecadien-1-ol (β-sitosterol), and α-tocopherol (Vitamin E) in the petroleum ether fraction of C. olitorius leaves.Conclusion: The results of the current study proved the presence of 3,5-DCQA, astragalin, and isoquercetin in the ethyl acetate fraction of C. olitorius leaves and catechin in the n-butanol after hydrolysis fraction of C. olitorius seeds.Â

    Phytochemical Characterization using GC-MS Analysis of Methanolic Extract of Moringa oleifera ( Family Moringaceae) Plant Cultivated in Iraq

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    Objective: The aim of the present study was to characterize the Moringa oleifera plant cultivated in Iraq for the presence of biologically active phyto-chemicals using methanolic extracts of the plant (leaves and seeds)  . This study was determined by using Gas Chromatography –Mass spectrometry, while the mass spectra of the compounds found in the extract was matched with the National Institute of Standards and Technology (NIST) library. Methods: In the present investigation, methanolic extracts of Moringa oleifera were screened for the presence of steroids, alkaloids, tannins, flavonoids, terpenoids, anthraquinoin and cardiac glycosides  by standard qualitative test procedures and further this study was extended by analyzing the potent bioactive compounds in the methanolic extract of plant using GC-MS analysis. Results:  reveal the presence of different compounds (about 100 compound)  in the Moringa plant extract  among them alkaloids, terpenoids  steroids, saturated and unsaturated fatty acid, aromatic and aliphatic hydrocarbon, polyphenolic compounds . GC-MS was done using the database of National Institute of standard and Technology (NIST). Conclusion: Results confirmed the presence of therapeutically potent compounds in the Moringa extract predominantly steroids, flavonoids and terpenoids. Keywords: Moringa oleifera, biologically active, Phytochemicals, GC-MS analysis

    Studying the Effect of Kaolin Nano Particles on the Hydrophobicity ‎Behavior of Polystyrene Nanofibers Prepared by Electrospinning ‎Technique

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    يهدف هذا البحث الى  دراسة تاثير دقائق الكاؤولين النانوية على نسيج من الألياف النانوية المصنوع من ألياف البوليسترين النانوية. تم استخدام طريقة الغزل الكهربائي لإنشاء الالياف النانوية  المسلحة بدقائق الكاؤولين . خضعت جسيمات الكاؤولين المستخدمة في هذه الدراسة لاختبار الأشعة السينية ، وكانت النتيجة مطابقة للاختبار النموذجي . أظهرت نتائج AFM أن الكاؤولين النانوي تتمتع بنعومة عالية عالية (1.5 نانومتر) ، ومساحة سطح جيدة ، وعامل تحمل عالي (6) ، بالإضافة إلى خصائص أخرى مرغوبة. تم استخدام جزيئات الكاؤولين النانوية بنسب مختلفة لمعرفة تأثير الكاؤولين على السلوك الكاره للماء لألياف البوليسترين النانوية. أظهرت النتائج أن الألياف النانوية المنتجة يمكن أن تمتلك خاصية التنظيف الذاتي لأنها كارهة للماء (لا تستطيع امتصاص الماء) ولها زاوية تلامس تبلغ 87 درجة ، والتي زادت بعد إضافة جسيمات الكاولين النانوية (139 درجة). تمت دراسة تأثير معاملات المحلول ، مثل تركيز المحلول ، واللزوجة  على أقطار الألياف الناتجة في هذه الدراسة. تم تحديد التركيز النموذجي لمحلول البولي ستايرين وكان 0.12 g/ml باستقرار المعلمات الأخرى، حيث كانت الالياف الناتجة باقطار ملائمة بحدود 100 نانومتر وخالية من الفقاعات  ، تم فحص تأثير زيادة تركيز دقائق الكاؤولين على اقطار الالياف النانوية الناتجة . اثبتت النتائج ان قطر الالياف النانوية يزداد عند زيادة تركيز دقائق الكاؤولين النانوية حيث تزداد لزوجة المحاليل بزيادة تركيز دقائق الكاؤولين النانوية مع ثبوت باقي العوامل ، وأظهرت النتائج أنه عند زيادة تركيز جزيئات الكاؤولين النانوية تزداد زاوية الترطيب حتى تصل إلى 139 درجة. This project promotes the creation of a nanofiber fabric made of polystyrene nanofibers reinforced with locally produced kaolin nanoparticles. An electrospinning procedure was used to create the overlapping fibers. The kaolin particles employed in this study underwent an X-ray test, and the outcome matched that of the typical test. The AFM results demonstrated that the nano-kaolin has a high fineness (1.5 nanometers), good surface area, and a high tolerance factor 6, in addition to other desirable properties. Kaolin nanoparticles in various ratios were utilized to evaluate the effect of kaolin on the hydrophobic behavior of polystyrene nanofibers. The results showed that the produced nanofibers could self-clean since they were hydrophobic (could not absorb water) and had a contact angle of 87 degrees, which increased after adding kaolin nanoparticles (139 o) . This study also looked into how solution characteristics like solution concentration and viscosity affected the diameters of the resulting fibers. The impact of nano Kaolin concentrations on the diameters of the resulting fibers was examined for the ideal concentration (0.12 g/ml), which was achieved because free-bead nanofibers were produced. This concentration was previously determined with the stability of the other parameters. The findings demonstrated that as kaolin nanoparticle concentration rises, so do nanofiber diameters because rising solution viscosities increase the number of nanofibers reinforced with kaolin nanoparticles. Additionally, wetting angle rises until it reaches 139 degrees.                   &nbsp

    Study the Effect of adding PAAM on Some Physical Properties of PVA Polymer

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    Some of physical properties of dissolves Polyvinyl Alcohol (PVA) in distilled water had been studied at different concentrations (0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8% and 0.9%) (gm. /ml) before and after adding (1, 1.5) gm. Of Polyacrylamide (PAAM) for all concentrations these are (Rheological and Electrical properties). The Rheological properties such as shear Viscosity, relative Viscosity, Specific Viscosity and reduced Viscosity are measured. The results show that all these properties are increasing with the increase of the polymer concentration before and after adding except reduced Viscosity is decreasing with the increase of the polymer concentration before adding. The electrical conductivity have been investigated at (293K.). Results also shows that adding (PAAM) polymer to (PVA) enhances the conductivity, then the molar conductivity and degree of dissociation were calculated and it depending on the values of density, concentration and type of solute and solvent. Keywords: (PVA) solution, (PAAM) solution, Rheological properties, Electrical properties

    Ultrasonic study of PVA and PVA / PAAM film composites prepared by casting method

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    The PVA/PAAM composite membranes of poly vinyl alcohol and Polyacrylamide were prepared by casting method, the appropriate weights of PVA were variable (0.25, 0.5, 0.75, 1 and 1.25 gm) dissolved in (25ml) of distilled water under stirring and heat (70?C) for (30 min.) then different weights (0.15 and 0.3 gm.) of PAAM  were added to each PVA . In order to evaluate the mechanical properties of PVA and PVA/ PAAM composite the ultrasonic measurements were performed at the samples. These properties   are velocity of ultrasonic waves, absorption coefficient of ultrasonic waves, relaxation amplitude, specific acoustic impedance, bulk modules and compressibility. The results show that all these properties are increasing with the increase of the polymer thickness except compressibility is decreasing with increase the thickness; results also show that when adding PAAM these properties have higher values than    those before increasing except compressibility is decreasing. Results also show that adding PAAM polymer to PVA enhances these properties as a result of high values after addition. Keywords: polyvinyl alcohol; Polyacrylamide; mechanical properties; casting method
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