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Tytuł:
Measure valued solutions for systems governed by neutral differential equations on Banach spaces and their optimal control
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729292.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
neutral differential equations
Banach spaces
optimal control
Opis:
In this paper we consider the question of existence of measure valued solutions for neutral differential equations on Banach spaces when there is no mild solutions. We prove the existence of measure solutions and their regularity properties. We consider also control problems of such systems and prove existence of optimal feedback controls for some interesting a-typical control problems.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2013, 33, 1; 89-109
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal control of ∞-dimensional stochastic systems via generalized solutions of HJB equations
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729348.pdf
Data publikacji:
2001
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
optimal control
stochastic systems
infinite dimension
HJB equation
stationary feedback control
Opis:
In this paper, we consider optimal feedback control for stochastc infinite dimensional systems. We present some new results on the solution of associated HJB equations in infinite dimensional Hilbert spaces. In the process, we have also developed some new mathematical tools involving distributions on Hilbert spaces which may have many other interesting applications in other fields. We conclude with an application to optimal stationary feedback control.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2001, 21, 1; 97-126
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Weak compactness in the space of operator valued measures $M_ba(Σ,(X,Y))$ and its applications
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729361.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
space of operator valued measures
weak compactness
semigroups of bounded linear operators
optimal structural control
Opis:
In this note we present necessary and sufficient conditions characterizing conditionally weakly compact sets in the space of (bounded linear) operator valued measures $M_{ba}(Σ,(X,Y))$. This generalizes a recent result of the author characterizing conditionally weakly compact subsets of the space of nuclear operator valued measures $M_{ba}(Σ,₁(X,Y))$. This result has interesting applications in optimization and control theory as illustrated by several examples.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2011, 31, 2; 231-247
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal control of systems determined by strongly nonlinear operator valued measures
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729396.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
evolution equations
strongly nonlinear operator valued measures
existence of solutions
regularity properties
optimal control
Opis:
In this paper we consider a class of distributed parameter systems (partial differential equations) determined by strongly nonlinear operator valued measures in the setting of the Gelfand triple V ↪ H ↪ V* with continuous and dense embeddings where H is a separable Hilbert space and V is a reflexive Banach space with dual V*. The system is given by
dx + A(dt,x) = f(t,x)γ(dt) + B(t)u(dt), x(0) = ξ, t ∈ I ≡ [0,T]
where A is a strongly nonlinear operator valued measure mapping Σ × V to V* with Σ denoting the sigma algebra of subsets of the set I and f is a nonlinear operator mapping I × H to H, γ is a countably additive bounded positive measure and the control u is a suitable vector measure. We present existence, uniqueness and regularity properties of weak solutions and then prove the existence of optimal controls (vector valued measures) for a class of control problems.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2008, 28, 1; 165-189
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vector and operator valued measures as controls for infinite dimensional systems: optimal control
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729468.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
evolution equations
Banach spaces
operator valued measures
strong operator topology
existence of solutions
optimal control
Opis:
In this paper we consider a general class of systems determined by operator valued measures which are assumed to be countably additive in the strong operator topology. This replaces our previous assumption of countable additivity in the uniform operator topology by the weaker assumption. Under the relaxed assumption plus an additional assumption requiring the existence of a dominating measure, we prove some results on existence of solutions and their regularity properties both for linear and semilinear systems. Also presented are results on continuous dependence of solutions on operator and vector valued measures, and other parameters determining the system which are then used to prove some results on control theory including existence and necessary conditions of optimality. Here the operator valued measures are treated as structural controls. The paper is concluded with some examples from classical and quantum mechanics and a remark on future direction.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2008, 28, 1; 95-131
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impulsive perturbation of C₀-semigroups and stochastic evolution inclusions
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729564.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
impulsive perturbations
C₀-semigroups
stochastic systems
differential inclusions
vector measures
impulsive controls
Opis:
In this paper, we consider a class of infinite dimensional stochastic impulsive evolution inclusions. We prove existence of solutions and study properties of the solution set. It is also indicated how these results can be used in the study of control systems driven by vector measures.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2002, 22, 1; 125-149
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal control of general McKean-Vlasov stochastic evolution equations on Hilbert spaces and necessary conditions of optimality
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729626.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
McKean-Vlasov stochastic differential equation
Hilbert spaces
relaxed controls
existence of optimal controls
Opis:
In this paper we consider controlled McKean-Vlasov stochastic evolution equations on Hilbert spaces. We prove existence and uniqueness of solutions and regularity properties thereof. We use relaxed controls, adapted to a current of sub-sigma algebras generated by observable processes, and taking values from a Polish space. We introduce an appropriate topology based on weak star convergence. We prove continuous dependence of solutions on controls with respect to appropriate topologies. Theses results are then used to prove existence of optimal controls for Bolza problems. Then we develop the necessary conditions of optimality based on semi-martingale representation theory on Hilbert spaces. Next we show that the adjoint processes arising from the necessary conditions optimality can be constructed from the solution of certain BSDE.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2015, 35, 2; 165-195
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Topological dual of $B_∞(I, ₁(X,Y))$ with application to stochastic systems on Hilbert space
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729390.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
representation theory
topological dual
finitely additive operator-valued measures
polish space
Hilbert space
stochastic systems
structural control
uncertainty abatement
Opis:
In this paper, we prove that the topological dual of the Banach space of bounded measurable functions with values in the space of nuclear operators, furnished with the natural topology, is isometrically isomorphic to the space of finitely additive linear operator-valued measures having bounded variation in a Banach space containing the space of bounded linear operators. This is then applied to a stochastic structural control problem. An optimal operator-valued measure, considered as the structural control, is to be chosen so as to minimize fluctuation (volatility). Both existence of optimal policy and necessary conditions of optimality are presented including a conceptual algorithm.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2009, 29, 1; 67-90
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A relaxation theorem for partially observed stochastic control on Hilbert space
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729417.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
partially observed control
infinite dimensional Hilbert space
relaxed controls
Zakai equation
Opis:
In this paper, we present a result on relaxability of partially observed control problems for infinite dimensional stochastic systems in a Hilbert space. This is motivated by the fact that measure valued controls, also known as relaxed controls, are difficult to construct practically and so one must inquire if it is possible to approximate the solutions corresponding to measure valued controls by those corresponding to ordinary controls. Our main result is the relaxation theorem which states that the set of solutions corresponding to ordinary controls is weakly dense in the set of solutions corresponding to relaxed controls. This is presented in Theorem 5.3 after giving some existence results on optimal controls for the infinite dimensional Zakai equation used for its proof.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2007, 27, 2; 295-314
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Infinite dimensional uncertain dynamic systems on Banach spaces and their optimal output feedback control
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729515.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
partially observed
uncertain systems
stochastic systems
operator valued functions
feedback operators
existence of optimal operators in the presence of uncertainty
Opis:
In this paper we consider a class of partially observed semilinear dynamic systems on infinite dimensional Banach spaces subject to dynamic and measurement uncertainty. The problem is to find an output feedback control law, an operator valued function, that minimizes the maximum risk. We present a result on the existence of an optimal (output feedback) operator valued function in the presence of uncertainty in the system as well as measurement. We also consider uncertain stochastic systems and present similar results on the question of existence of optimal feedback laws.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2015, 35, 1; 65-87
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stochastic evolution equations on Hilbert spaces with partially observed relaxed controls and their necessary conditions of optimality
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729524.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
differential equations
Hilbert spaces
relaxed controls
optimal control
necessary conditions of optimality
Opis:
In this paper we consider the question of optimal control for a class of stochastic evolution equations on infinite dimensional Hilbert spaces with controls appearing in both the drift and the diffusion operators. We consider relaxed controls (measure valued random processes) and briefly present some results on the question of existence of mild solutions including their regularity followed by a result on existence of partially observed optimal relaxed controls. Then we develop the necessary conditions of optimality for partially observed relaxed controls. This is the main topic of this paper. Further we present an algorithm for computation of optimal policies followed by a brief discussion on regular versus relaxed controls. The paper is concluded by an example of a non-convex problem which is readily solvable by our approach.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2014, 34, 1; 105-129
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal control of impulsive stochastic evolution inclusions
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729552.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
impulsive perturbations
C₀-semigroups
stochastic systems
differential inclusions
vector measures
optimal controls
Opis:
In this paper, we consider a class of infinite dimensional stochastic impulsive evolution inclusions driven by vector measures. We use stochastic vector measures as controls adapted to an increasing family of complete sigma algebras and prove the existence of optimal controls.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2002, 22, 2; 155-184
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A general class of McKean-Vlasov stochastic evolution equations driven by Brownian motion and Lèvy process and controlled by Lèvy measure
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729570.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
McKean-Vlasov stochastic differential equation
Hilbert spaces
existence of optimal controls
Opis:
In this paper we consider McKean-Vlasov stochastic evolution equations on Hilbert spaces driven by Brownian motion and L`evy process and controlled by L`evy measures. We prove existence and uniqueness of solutions and regularity properties thereof. We consider weak topology on the space of bounded Le´vy measures on infinite dimensional Hilbert space and prove continuous dependence of solutions with respect to the Le´vy measure. Then considering a certain class of Le´vy measures on infinite as well as finite dimensional Hilbert spaces, as relaxed controls, we prove existence of optimal controls for Bolza problem and some simple mass transport problems
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2016, 36, 2; 181-206
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measure valued solutions for stochastic evolution equations on Hilbert space and their feedback control
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729584.pdf
Data publikacji:
2005
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
stochastic differential equations
Hilbert space
measurable vector fields
finitely additive measure solutions
optimal feedback controls
Opis:
In this paper, we consider a class of semilinear stochastic evolution equations on Hilbert space driven by a stochastic vector measure. The nonlinear terms are assumed to be merely continuous and bounded on bounded sets. We prove the existence of measure valued solutions generalizing some earlier results of the author. As a corollary, an existence result of a measure solution for a forward Kolmogorov equation with unbounded operator valued coefficients is obtained. The main result is further extended to cover Borel measurable drift and diffusion which are assumed to be bounded on bounded sets. Also we consider control problems for these systems and present several results on the existence of optimal feedback controls.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2005, 25, 1; 129-157
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Controllability of evolution equations and inclusions driven by vector measures
Autorzy:
Ahmed, N.U.
Powiązania:
https://bibliotekanauki.pl/articles/729615.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
controlability
impulsive systems
differential inclusions
Hilbert spaces
vector valued measures
C₀ semigroups
Opis:
In this paper, we consider the question of controllability of a class of linear and semilinear evolution equations on Hilbert space with measures as controls. We present necessary and sufficient conditions for weak and exact (strong) controllability of a linear system. Using this result we prove that exact controllability of the linear system implies exact controllability of a perturbed semilinear system. Controllability problem for the semilinear system is formulated as a fixed point problem on the space of vector measures and is concluded controllability from the existence of a fixed point. Our results cover impulsive controls as well as regular controls.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2004, 24, 1; 49-72
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved photoresponse of porous silicon photodetectors by embedding CdS nanoparticles
Autorzy:
Abd, Ahmed N.
Powiązania:
https://bibliotekanauki.pl/articles/1193949.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CdS
Nanoparticles
PSi
Photodetector
SEM
XRD
Opis:
In this research, the nanocrystalline porous silicon (PSi) films are prepared by electrochemical etching of p types silicon wafers with 15 mA/cm2 etching current densities and 15 min etching time on the formation nanosized pore array. PSi was characterized by the measurement of XRD, FTIR spectroscopy and atomic force microscopy properties (AFM). We have estimated crystallites size from X-Ray diffraction about nanoscale for PSi and Atomic Force microscopy confirms the nanometric size Chemical fictionalization during the electrochemical etching show on the surface chemical composition of PSi. The atomic force microscopy investigation shows the rough silicon surface. Also, it is reported the preparation of colloidal CdS nanoparticles NPs prepared by laser ablation in liquid (LAL) technique by irradiating with a Nd:YAG laser pulses CdS target immersed in methanol and varying the laser fluence 1.32 J/cm2. The structural, morphological and optical of CdS NPs has been studied. XRD measurement disclosed that the CdS NPs were of wurtzite hexagonal crystal structure. Transmission electron microscopy (TEM) investigation revealed that the synthesized CdS particles are spherical and have an average particle size in the range of (25 nm). AFM investigations showed that the produced CdS particles have ball-shape with good disposability. The energy band gap of CdS NPs prepared with 1.32 J/cm2 laser fluence has been determined from optical properties and found to be in the range (2.9 eV). Optical constants of CdS NPs were determined from transmittance and reflectance spectra.The effect of CdS NPs diffusion on properties of PSi Photodetector have reported which reveals that improving in (Al/PSi/Si/Al). The results show that a linear relationship between 1/C2 and reverse bias voltage was obtained. The built-in potential have values depending on the etching time current density and laser flunce. Al/CdSe/PSi/Si/Al photodetector hetrojunction have two peaks of response located at 415 nm and (700 -800nm) with max sensitivity 0.6 A/W. The maximum specific detectivity is 6.8×〖10〗^12 cm•〖Hz〗^(1/2) 〖•W〗^(-1) at 770 nm wavelength.
Źródło:
World Scientific News; 2015, 19; 32-49
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stochastic diffrential equations on Banach spaces and their optimal feedback control
Autorzy:
Ahmed, N.U.
Powiązania:
https://bibliotekanauki.pl/articles/952179.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
stochastic differential equations
Banach spaces
optimal feedback control
objective functionals
Lévy-Prohorov metric
Hausdorff dimension
time-optimal problems
Opis:
In this paper we consider stochastic differential equations on Banach spaces (not Hilbert). The system is semilinear and the principal operator generating a C₀-semigroup is perturbed by a class of bounded linear operators considered as feedback operators from an admissible set. We consider the corresponding family of measure valued functions and present sufficient conditions for weak compactness. Then we consider applications of this result to several interesting optimal feedback control problems. We present results on existence of optimal feedback operators.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2012, 32, 1; 87-109
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Physical Properties of Copper Oxide Thin Films Prepared by Electrolysis Method
Autorzy:
Oudah, Mustafa H.
Mazin, H. Hasan
Abd, Ahmed N.
Powiązania:
https://bibliotekanauki.pl/articles/1065248.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
copper oxide
drop-casting method
electrolysis
quantum size effect
thin films
Opis:
The aim of this paper is to study the properties of copper oxide thin films prepared by electrolysis method and deposited on glass substrates by drop-casting method at different annealing temperatures. Copper oxide colloidal was successfully prepared by electrolysis method. The X-ray diffraction confirms the polycrystalline structure of the films. Atomic force microscopy shows that the increase in the annealing temperature improves the surface morphology, increases the grain size and removes the cracks. The best optical transmittance was for the film annealed at 200 ºC. The bandgap decreases from 3.35 eV to 3.15 eV as a result of increasing the annealing temperature. The wide bandgap that obtained in this study is due to quantum size effect.
Źródło:
World Scientific News; 2019, 135; 59-70
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of water treatment plants quality in Basrah Province, by factor and cluster analysis
Autorzy:
Al Saad, Zainb A.A.
Hamdan, Ahmed N.A.
Powiązania:
https://bibliotekanauki.pl/articles/293213.pdf
Data publikacji:
2020
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
cluster analysis (CA)
factor analysis (FA)
multivariate statistics
the Shatt Al Arab River
water quality
water treatment plant
Opis:
The Shatt Al Arab River (SAAR) is a major source of raw water for most water treatment plants (WTP’s) located along with it in Basrah province. This study aims to determine the effects of different variables on water quality of the SAAR, using multivariate statistical analysis. Seventeen variables were measured in nine WTP’s during 2017, these sites are Al Hussain (1), Awaissan (2), Al Abass (3), Al Garma (4), Mhaigran (5), Al Asmaee (6), Al Jubaila (7), Al Baradia (8), Al Lebani (9). The dataset is treated using principal component analysis (PCA) / factor analysis (FA), cluster analysis (CA) to the most important factors affecting water quality, sources of contamination and the suitability of water for drinking and irrigation. Three factors are responsible for the data structure representing 88.86% of the total variance in the dataset. CA shows three different groups of similarity between the sampling stations, in which station 5 (Mhaigran) is more contaminated than others, while station 3 (Al Abass) and 6 (Al Asmaee) are less contaminated. Electrical conductivity (EC) and sodium adsorption ratio (SAR) are plotted on Richard diagram. It is shown that the samples of water of Mhaigran are located in the class of C4-S3 of very high salinity and sodium, water samples of Al Abass station, are located in the class of C3-S1 of high salinity and low sodium, and others are located in the class of C4-S2 of high salinity and medium sodium. Generally, the results of most water quality parameters reveal that SAAR is not within the permissible levels of drinking and irrigation.
Źródło:
Journal of Water and Land Development; 2020, 46; 10-19
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cotton leaf blight disease caused by Alternaria alternata in Sudan
Autorzy:
Mohamed, O.E.
Beshir, M.M.
Ahmed, N.E.
Powiązania:
https://bibliotekanauki.pl/articles/2084617.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Alternaria alternata
conidia
Gossypium spp.
internal transcribed spacer
(ITS)
morphological variability
pathogenicity
Opis:
Genetically modified Bt cotton (Gossypium hirsutum) leaves with typical symptoms of Alternaria early blight disease resembling that of tomato and potato were observed in the main cotton growing schemes in Sudan. Symptoms on leaves appeared as either brown 2leaf spot with gray centers or leaf blight with concentric rings. Pathogenicity tests using isolates with both symptoms showed that the isolated fungi were highly pathogenic to both G. hirsutum and G. barbadense cotton varieties. Alternaria alternata isolated from infected tomato and potato leaves with early blight symptoms was included for comparison. Microscopic examination showed that the mean length of conidia from cotton, tomato and potato isolates ranged from 26.25 to 45.45 µm, while the width ranged from 9.56 to 13.64 µm. The mean number of transverse septa among all isolates was 3.4 to 5.7 and the peak length ranged from 3.75 to 7.8 µm. Based on morphological characteristics the two isolates from cotton were identified as A. alternata. Genomic DNA was extracted directly from fungal cultures grown on potato dextrose agar (PDA) plates using a Zymo Research Quick DNA kit. A species-specific primer using the internal transcribed spacer ribosomal DNA (ITS rDNA) PCR scoring indicated the presence of A. alternata using primer pair ITS4/ITS5. Amplifications of the internal transcribed spacer region of 600 bp revealed 100% identity of the isolated fungus from cotton with A. alternata from tomato and potato. These data oblige us to reconsider the presence of A. alternata in the four main cotton growing schemes in Sudan while these symptoms have always been described for tomato and potato early blight disease.
Źródło:
Journal of Plant Protection Research; 2019, 59, 3; 412-417
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectroscopic Methods Studies in Polymer
Autorzy:
Rahi, Saad Khalid
Hassan, Ehssan Salah
Abd, Ahmed N.
Powiązania:
https://bibliotekanauki.pl/articles/1190136.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
ESCA
polymer
Fluorescence spectra
Excitation wavelength
Opis:
The physico – chemical changes induced in polymers following to radiation can be studied by a range of spectroscopic techniques. Recent developments in instrumentation and data analysis procedures in electronic, vibrational and magnetic resonance spectroscopes have provided considerable new insights, into polymer structure and behavior. The applications of these spectroscopic methods in polymer studies are reviewed with emphasis on their utility in investigations of radiation effects on macromolecules
Źródło:
World Scientific News; 2016, 42; 41-53
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of molarity on the structural and optical properties of ZnO thin films deposit by CSP
Autorzy:
Habubi, Nadir F.
Abood, Ziad M.
Algamel, Ahmed N.
Powiązania:
https://bibliotekanauki.pl/articles/1193915.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Urbach energy
ZnO
ZnO thin films
optical properties
structural properties
Opis:
ZnO thin films have been prepared by chemical spray pyrolysis technique CSP). XRD pattern reveals that the preferred orientation was varied with concentration, topography analysis was done by AFM micrograph which confirm the existence of nonstructural films. The optical properties was done by recorded the transmittane and absorbance which were affected by an increase in concentration. The values of optical energy gap obtained from Tauc relation were 3.17, 3.18 and 3.19 eV for 0.05, 0.1 and 0.5 M respectively. Urbach energy confirms the decrease in band tail as the concentration increase.
Źródło:
World Scientific News; 2015, 22; 55-69
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication and Characterization of Porous Silicon
Autorzy:
Duaa, Jabbar Hussein
Alzubaidy, Muneer H. Jaduaa
Abd, Ahmed N.
Powiązania:
https://bibliotekanauki.pl/articles/1157178.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Anodization
Nanocrystalline porous silicon
XRD
porous silicon
Opis:
In this work, nanocrystalline porous silicon layers were fabricated by photoelectrochemical etching of n type silicon (n-Si) wafer. Different etching time (15, 20, 25 and 30) min and 10 mA/cm2 current density were tested to study their effect on the formation nanosized pore array. Porous silicon is investigation by X-Ray diffractions (XRD) and atomic force microscopy properties (AFM). Crystallites size was estimated by X-Ray diffraction. Atomic Force microscopy confirmed the nonmetric size Chemical Anodization the electrochemical etching was noticed of PS. The atomic force microscopy investigation showed the rough silicon surface which increased with etching time porous structure nucleates which leads to an increase in the depth and width (diameter) of surface pits.
Źródło:
World Scientific News; 2018, 94, 2; 321-328
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biological synthesis of Titanium Dioxide nanoparticles by Curcuma longa plant extract and study its biological properties
Autorzy:
Abdul Jalill, Raghad DH.
Nuaman, Rasha S.
Abd, Ahmed N.
Powiązania:
https://bibliotekanauki.pl/articles/1182934.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
biosynthesis
curcuma longa
damping-off
nanoparticles
plant
tio2
Opis:
The objective of this study was biosynthesis of titanium dioxide nanoparticles (TiO2 NPs) using Curcuma longa aqueous extract and characterize them. Study their effect on the growth, sporulation, pathogenicity of Fusarium graminearum and some wheat plants parameters compared with standards industrials nanoparticles. C. longa aquatic extract was used to biosynthesis TiO2 NPs by two methods. At first method, TiO2 was found in both colloidal solutions (CS) and nanopawder while it found in jest nanopawder in second method. All biosynthetic nanoparticles were in nano size. It was: 91.37 nm, 76.36 nm of (CS) and nanopawder for first methods respectively while it was 92.6 nm of nanopawder in second method. All nanoparticles have good optical properties. Crystal’s shape of nanopawder were in three form: anatase, rutilr and brookite and it was anatase in colloidal solutionat first method while it was pure anatase innanopawder when at second method. The average crystallite size of was calculate by Scherer's equation, it was 43.088 nm and 22.881 nm for nanopawder and colloidal solution respectively at first method. It was 45.808 nm for nanopawder at second method. All concentrations of nanoparticles were reduced fungal and spores. These decreasing were more effective using biosynthetic compare with industrial synthetic nanoparticles. There were reductions in damping-off caused by F. graminearum by biosynthetic NBs in both varieties of plant (Al-Rasheed and Tamuze-2). These was better than the effect of industrial synthetic nanoparticles. The resistance to damping off and the growth of plant in Al-Rasheed variety was more sensitive compared with Tamuze-2 variety especially at higher concentrations. There were decrease in all plant's parameters at most concentrations of TiO2 biological synthetic compare with industrial synthetic nanoparticles in Al-Rasheed variety, while there were inductions in some plant's parameters by biosynthetic nanoparticles compared with industrial synthetic in Tamuze-2 variety. Finally, C. longa can be used to biosynthesis TiO2 NPs with good biological properties.
Źródło:
World Scientific News; 2016, 49, 2; 204-222
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical model to determine the Porosity and refractive index of porous silicon type-n by using Atomic force microscope
Autorzy:
Abdulridha, Wasna'a M.
Abd, Ahmed N.
Dawood, Mohammed O.
Powiązania:
https://bibliotekanauki.pl/articles/1193012.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Atomic Force Microscope
Porous silicon
n-PS
porosity
refractive index
thickness
Opis:
Porous silicon (PS) layer was produced by photochemical etching process at (5, 7, 10, 12 and 15) etching time and 7 mA/cm2 current density then after investigation by Atomic Force Microscope (AFM) the thickness of PS layer from about 3.4 µm to 15.8 µm was determined. The surface of porous silicon is formed from small pyramids with porous structure, where the porosity of n-PS is from ≈ (32-72%). Porous silicon layer formed on the silicon substrates by photochemical etching contains also the nanopores with diameter about (16.41-42) nm in current density (7mA/cm2). The porosity and thickness was determined from AFM results and compared with the result from the usually measured porosity and thickness through a gravimetric method we found that the values of porosity and thickness calculated from two methods are approximately similar to each other with few difference, the influence of structure changes on optical properties such as refractive index, which decreases exponentially with porosity.
Źródło:
World Scientific News; 2016, 28; 29-40
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 44

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