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Search Results: 1 - 10 of 463052 matches for " Tawfik A. Saleh "
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Spectroscopy: Between Modeling, Simulation and Practical Investigation  [PDF]
Tawfik A. Saleh
Spectral Analysis Review (SAR) , 2014, DOI: 10.4236/sar.2014.21001
Abstract: Spectroscopy
Detection: From Electrochemistry to Spectroscopy with Chromatographic Techniques, Recent Trends with Nanotechnology  [PDF]
Tawfik A. Saleh
Detection (Detection) , 2014, DOI: 10.4236/detection.2014.24005
Abstract: The detection of trace levels of chemical, biological and other analytes has many important applications, including industry, forensics and environmental monitoring. Detection Journal is an international journal dedicated to the latest advancement of all areas that are related to detection. Nanotechnology based detection techniques may provide major advantages of low detection limits and rapid testing. This may allow scientists to know early about the case and provide the potential of stopping the problem at earlier stages.
Orders of Fermi- and Plasma-Accelerations of Cosmic Rays
A. Tawfik,A. Saleh
Physics , 2010,
Abstract: The generic acceleration model for ultra high energy cosmic rays, which has been introduced in {\tt 1006.5708 [astro-ph.HE]}, suggests various types of electromagnetic interactions between cosmic charged particles and the different types of the plasma fields, which are assumed to have general configurations, spatially and temporally. The well-known Fermi acceleration mechanisms are also included in the model. Meanwhile Fermi mechanisms in non-relativistic limit adhere first- and second-order of $\beta$, the ratio of particle's velocity relative to the velocity of the stellar magnetic cloud, in the plasma field sector, $\beta$ does not play any role, i.e. zero-order. In the relativistic limit, the orders of Fermi acceleration are only possible, when applying the corresponding conditions, either elastic scatterings or shock waves. Furthermore, it is found that the coefficients of $\beta$ are functions of the initial and final velocities and the characteristic Larmor radius.
Application of dc and mark-space bias differential electrolytic potentiometry for determination of cyanide using a programmable syringe pump
Tawfik A. Saleh,A. M. Abulkibash
Applied Water Science , 2011, DOI: 10.1007/s13201-011-0010-5
Abstract: This paper describes a rapid sequential injection titration method for the determination of cyanide in aqueous solutions. Mercuric nitrate was used as a titrant and a pair of gold-amalgam electrodes as an indicating system. The technique of differential electrolytic potentiometry using both mark-space bias (m.s.b.) and dc current for polarization was employed. The optimum values of current and percentage bias were 5 μA and 13%, respectively. The effects of dispense time, volume of analyte, supporting electrolyte, and the concentration of titrant were investigated. The results obtained are in agreement with those of the standard method (APHA), with a relative standard deviation of 1.43%, t = 0.783, F = 1.713. A sampling rate of about 20 samples per hour was achieved with good reproducibility and lower consumption of reagents.
Acceleration and Particle Field Interactions of Cosmic Rays I: Formalism
A. Tawfik,A. Saleh,M. T. Ghoneim,A. A. Hady
Physics , 2010, DOI: 10.3844/pisp.2012.64.73
Abstract: The acceleration of ultra high energy cosmic rays is conjectured to occur through various interactions with the electromagnetic fields in different astrophysical objects, like magnetic matter clumps, besides the well-known shock and stochastic Fermi mechanisms. It is apparent that the latter are not depending on the particle's charge, quantitatively. Based on this model, a considerable portion of the dynamics, that derives a charged particle parallel to a magnetic field $\mathbf{B}$ and under the influence of a force $\mathbf{F}$, is assumed to be composed of an acceleration by a non-magnetic force $\mathbf{F}_{\parallel}$ and a gyromotion along $\mathbf{B}$ direction, plus drifts in the direction of $\mathbf{F}_{\perp}$. The model and its formalism are introduced. Various examples for drift motions and accelerating forces are suggested. The formalism is given in a non-relativistic version. Obviously, the translation into the relativistic version is standard. In a forthcoming work, a quantitative estimation of the energy gained by charged cosmic rays in various astrophysical objects will be evaluated.
Acceleration and Particle Field Interactions of Cosmic Rays II: Calculations
A. Tawfik,A. Saleh,M. T. Ghoneim,A. Hady
Physics , 2010,
Abstract: Based on the generic acceleration model, which suggests different types of electromagnetic interactions between the cosmic charged particles and the different configurations of the electromagnetic (plasma) fields, the ultra high energy cosmic rays are studied. The plasma fields are assumed to vary, spatially and temporally. The well-known Fermi accelerations are excluded. Seeking for simplicity, it is assumed that the energy loss due to different physical processes is negligibly small. The energy available to the plasma sector is calculated in four types of electromagnetic fields. It has been found that the drift in a time--varying magnetic field is extremely energetic. The energy scale widely exceeds the Greisen-Zatsepin-Kuzmin (GZK) cutoff. The polarization drift in a time--varying electric field is also able to raise the energy of cosmic rays to an extreme value. It can be compared with the Hillas mechanism. The drift in a spatially--varying magnetic field is almost as strong as the polarization drift. The curvature drift in a non--uniform magnetic field and a vanishing electric field is very weak.
Evaluation of the Hepatoprotective Effect of Aloe vera, Clematis hirsute, Cucumis prophetarum and Bee Propolis Against Experimentally Induced Liver Injury in Rats
Saleh I. Alqasoumi,Tawfik A. Al-Howiriny,Maged S. Abdel-Kader
International Journal of Pharmacology , 2008,
Abstract: In a project to search for new natural hepatroprotective agents 3 plant extracts; Aloe vera, Clematis hirsute and Cucumis prophetarum, in addition to Bee Propolis were studied. The ethanol extracts of the 3 plants and propolis were subjected to hepatoprotective assay using Wistar albino rats. Liver injury induced in rats using carbon tetrachloride. The biochemical parameters; serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP) and total bilirubin were estimated as reflection of the liver condition. Based on the good results of the biochemical parameters measurements, histopathological study was performed on the liver of rats treated with Propolis and Aloe vera. The livers of rats treated with Propolis showed good protection against the toxic effect of carbon tetrachloride. On the other hand treatment with Aloe vera extract failed to restore the normal appearance of hepatocytes. All the results were compared with silymarin, as a reference hepatoprotective drug.
On Horn Matrix Function H2(A,A′,B,B′;C;z,w) of Two Complex Variables under Differential Operator  [PDF]
Mohamed Saleh Metwally, Mahmoud Tawfik Mohamed, Ayman Shehata
Advances in Linear Algebra & Matrix Theory (ALAMT) , 2018, DOI: 10.4236/alamt.2018.82009
Abstract: The aim of this paper deals with the study of the Horn matrix function of two complex variables. The convergent properties, an integral representation of H2(A,A′,B,B′;C;z,w) is obtained and recurrence matrix relations are given. Some result when operating on Horn matrix function with the differential operator D and a solution of certain partial differential equations are established. The Hadamard product of two Horn’s matrix functions is studied, certain results as, the domain of regularity, contiguous functional relations and operating with the differential operator D and D2 are established.
Practical Study for the Effect of Speed, Direction of Acceleration and Type of Machine on Vibrations Transferred to the Steering Wheel Horticulture Tractor Type (Goldoni)  [PDF]
Ghazwan Ahmed Dahham, Saad Tawfik Muhamed, Shamel Mohammed Saleh
Engineering (ENG) , 2019, DOI: 10.4236/eng.2019.111005
Abstract: Field an experiment was carried out in the farms of Agriculture and forestry academy at University in Nineveh. The research was conducted to investigate a practical study for the effect of four forward speeds (1.9, 2.6, 3.8 and 4.7 km/hr.) and three acceleration direction of axes lateral, longitudinal and vertical, and two types machines control (Mower and Rotovators) on the vibrations transferred to the steering wheel horticulture tractor type (Goldoni). The vibration points on the handgrip were calculated and tested. Root mean square acceleration (RMS), given in m/sec2, was calculated. Results showed increased acceleration vibration of the three directions (longitudinal, lateral and vertical) transferred to the steering wheel tractor by increased forward speed. The Mower score recorded the highest acceleration vibration for the three directions of Rotovators. The levels of vibration emitted from tractor to hand an operator during the experiment was high comparing with standard mechanical vibration. Handgrip vibration intensity in the vertical direction is bigger than the lateral and longitudinal direction. The total vibration evaluating was denoted as the square root mean of the three sum value (lateral, longitudinal and vertical) directions. The paper purpose was measuring and analyzing vibration level transferred to the steering wheel and reduces the machine vibration. This paper is helpful for design in order to increase the develop safety systems in easy and economical way.
Cosmological Consequences of QCD Phase Transition(s) in Early Universe
Tawfik, A.
High Energy Physics - Phenomenology , 2008, DOI: 10.1063/1.3131505
Abstract: We discuss the cosmological consequences of QCD phase transition(s) on the early universe. We argue that our recent knowledge about the transport properties of quark-gluon plasma (QGP) should throw additional lights on the actual time evolution of our universe. Understanding the nature of QCD phase transition(s), which can be studied in lattice gauge theory and verified in heavy ion experiments, provides an explanation for cosmological phenomenon stem from early universe.
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