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Search Results: 1 - 10 of 460756 matches for " N. J. Hassan "
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The Harmonic Oscillator with Random Damping in Non-Markovian Thermal Bath  [PDF]
N. J. Hassan, A. Pourdarvish, J. Sadeghi
World Journal of Mechanics (WJM) , 2016, DOI: 10.4236/wjm.2016.68019
Abstract: In this paper, we define the harmonic oscillator with random damping in non-Markovian thermal bath. This model represents new version of the random oscillators. In this side, we derive the overdamped harmonic oscillator with multiplicative colored noise and translate it into the additive colored noise by changing the variables. The overdamped harmonic oscillator is stochastic differential equation driving by colored noise. We derive the change in the total entropy production (CTEP) of the model and calculate the mean and variance. We show the fluctuation theorem (FT) which is invalid at any order in the time correlation. The problem of the deriving of the CTEP is studied in two different examples of the harmonic potential. Finally, we give the conclusion and plan for future works.
An analytic model for a cooperative ballistic deposition in one dimension
M. K. Hassan,N. Wessel,J. Kurths
Physics , 2002, DOI: 10.1103/PhysRevE.67.061109
Abstract: We formulate a model for a cooperative ballistic deposition (CBD) process whereby the incoming particles are correlated with the ones already adsorbed via attractive force. The strength of the correlation is controlled by a tunable parameter $a$ that interpolates the classical car parking problem at $a=0$, the ballistic deposition at $a=1$ and the CBD model at $a>1$. The effects of the correlation in the CBD model are as follows. The jamming coverage $q(a)$ increases with the strength of attraction $a$ due to an ever increasing tendency of cluster formation. The system almost reaches the closest packing structure as $a\to\infty$ but never forms a percolating cluster which is typical to 1D system. In the large $a$ regime, the mean cluster size $k$ increases as $a^{1/2}$. Furthermore, the asymptotic approach towards the closest packing is purely algebraic both with $a$ as $q(\infty)-q(a) \sim a^{-1/2}$ and with $k$ as $q(\infty)-q(k) \sim k^{-1}$ where $q(\infty)\simeq 1$.
An Accurate Numerical Solution for the Modified Equal Width Wave Equation Using the Fourier Pseudo-Spectral Method  [PDF]
Hany N. Hassan
Journal of Applied Mathematics and Physics (JAMP) , 2016, DOI: 10.4236/jamp.2016.46110
Abstract: In this study, the numerical solution for the Modified Equal Width Wave (MEW) equation is presented using Fourier spectral method that use to discretize the space variable and Leap-frog method scheme for time dependence. Test problems including the single soliton wave motion, interaction of two solitary waves and interaction of three solitary waves will use to validate the proposed method. The three invariants of the motion are evaluated to determine the conservation properties of the generated scheme. Finally, a Maxwellian initial condition pulse is then studied. The L2 and L error norms are computed to study the accuracy and the simplicity of the presented method.
AGN Forecasts for the Cherenkov Telescope Array
T. Hassan,N. Mirabal,J. L. Contreras,for the CTA Consortium
Physics , 2012,
Abstract: The First Fermi-LAT catalog (1FGL) represents the most complete list of sources in the GeV sky to date. We use the reported 1FGL spectral parameters to extrapolate Fermi AGN spectra to the very-high energy (VHE) range (15 GeV - 300 TeV). The extrapolated VHE spectra are then attenuated using current estimations of the extragalactic background light (EBL) absorption as a function of redshift. Using the expected effective areas and background rates of the Cherenkov Telescope Array (CTA) from Monte Carlo simulations, we make a first order prediction of the AGN population accessible to CTA in the VHE sky. We find that CTA should easily triple the AGN detection rate of current ground-based Cherenkov telescopes. In addition, CTA will allow unprecedented access to high-redshift blazars out to z ~ 2, and hence will start to reveal the EBL shape with gamma-ray observations.
Gamma-Ray Active Galactic Nucleus Type through Machine-Learning Algorithms
T. Hassan,N. Mirabal,J. L. Contreras,I. Oya
Physics , 2012, DOI: 10.1093/mnras/sts022
Abstract: The Fermi Gamma-ray Space Telescope is producing the most detailed inventory of the gamma-ray sky to date. Despite tremendous achievements approximately 25% of all Fermi extragalactic sources in the Second Fermi LAT Catalogue (2FGL) are listed as active galactic nuclei (AGN) of uncertain type. Typically, these are suspected blazar candidates without a conclusive optical spectrum or lacking spectroscopic observations. Here, we explore the use of machine-learning algorithms - Random Forests and Support Vector Machines - to predict specific AGN subclass based on observed gamma-ray spectral properties. After training and testing on identified/associated AGN from the 2FGL we find that 235 out of 269 AGN of uncertain type have properties compatible with gamma-ray BL Lacs and flat-spectrum radio quasars with accuracy rates of 85%. Additionally, direct comparison of our results with class predictions made after following the infrared colour-colour space of Massaro et al. (2012) show that the agreement rate is over four-fifths for 54 overlapping sources, providing independent cross validation. These results can help tailor follow-up spectroscopic programs and inform future pointed surveys with ground-based Cherenkov telescopes.
Study of Optical and Electrical Properties of Nickel Oxide (NiO) Thin Films Deposited by Using a Spray Pyrolysis Technique  [PDF]
Ahmed J. Hassan
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.518212
Abstract: Nickel oxide (NiO) thin film has been deposited on a glass substrate at a temperature of 390°C ± 10°C using a simple and inexpensive spray pyrolysis technique. Nickel nitrate salt solution (Ni(NO3)2·6H2O) was employed to prepare the films and the film thickness was in order of 200 ± 5 nm. The structural, optical and electrical properties of NiO films were investigated using X-ray diffraction (XRD), visible spectrum, DC conductivity and Seebeck effect measurements. The results show that X-ray diffraction techniques have shown that prepared film is polycrystalline structure type cubic phase. The measurements of optical properties (transmittance (T) and absorbance (A)) of NiO films show that higher transmittance is 37.4% within the wavelength range (300 - 900 nm). Also the results have shown that the higher absorbance is 77.7%. The results of electrical properties have shown that at room temperature electrical conductivity is 1.3 × 10-5·cm)-1, and also results have shown that all the films are of p-type due to the negative Seebeck coefficient.
Local conserved charges in principal chiral models
J. M. Evans,M. Hassan,N. J. MacKay,A. J. Mountain
Physics , 1999, DOI: 10.1016/S0550-3213(99)00489-7
Abstract: Local conserved charges in principal chiral models in 1+1 dimensions are investigated. There is a classically conserved local charge for each totally symmetric invariant tensor of the underlying group. These local charges are shown to be in involution with the non-local Yangian charges. The Poisson bracket algebra of the local charges is then studied. For each classical algebra, an infinite set of local charges with spins equal to the exponents modulo the Coxeter number is constructed, and it is shown that these commute with one another. Brief comments are made on the evidence for, and implications of, survival of these charges in the quantum theory.
Conserved Charges and Supersymmetry in Principal Chiral Models
J. M. Evans,M. Hassan,N. J. MacKay,A. J. Mountain
Physics , 1997,
Abstract: We report on investigations of local (and non-local) charges in bosonic and supersymmetric principal chiral models in 1+1 dimensions. In the bosonic PCM there is a classically conserved local charge for each symmetric invariant tensor of the underlying group. These all commute with the non-local Yangian charges. The algebra of the local charges amongst themselves is rather more subtle. We give a universal formula for infinite sets of mutually commuting local charges with spins equal to the exponents of the underlying classical algebra modulo its Coxeter number. Many of these results extend to the supersymmetric PCM, but with local conserved charges associated with antisymmetric invariants in the Lie algebra. We comment briefly on the quantum conservation of local charges in both the bosonic and super PCMs.
Conserved charges and supersymmetry in principal chiral and WZW models
J. M. Evans,M. Hassan,N. J. MacKay,A. J. Mountain
Physics , 2000, DOI: 10.1016/S0550-3213(00)00257-1
Abstract: Conserved and commuting charges are investigated in both bosonic and supersymmetric classical chiral models, with and without Wess-Zumino terms. In the bosonic theories, there are conserved currents based on symmetric invariant tensors of the underlying algebra, and the construction of infinitely many commuting charges, with spins equal to the exponents of the algebra modulo its Coxeter number, can be carried out irrespective of the coefficient of the Wess-Zumino term. In the supersymmetric models, a different pattern of conserved quantities emerges, based on antisymmetric invariant tensors. The current algebra is much more complicated than in the bosonic case, and it is analysed in some detail. Two families of commuting charges can be constructed, each with finitely many members whose spins are exactly the exponents of the algebra (with no repetition modulo the Coxeter number). The conserved quantities in the bosonic and supersymmetric theories are only indirectly related, except for the special case of the WZW model and its supersymmetric extension.
Comparison of Binding Capacity and Affinity of Monoclonal Antibody towards Different Affinity Resins using High-throughput Chromatography Method
N. Pakiman,N.H. Isa,M.A. Abol Hassan,J.K. Walter
Journal of Applied Sciences , 2012,
Abstract: Protein-A Affinity chromatography is the widely used key method for purification of monoclonal antibodies. Selection of a most suitable affinity resin based on binding capacity and affinity is typically performed prior to optimization. Development of high-throughput chromatography method in 96-well filter plate significantly reduced consumption of antibody sample and shortens the experimental time as compared to a typical column chromatography approach. In this study, five different affinity resins were evaluated, rProtein-A FF, MabSelect Sure, ProSep-vA Ultra and two novel synthetically derived affinity ligands immobilized on agarose media, the GF1 and GF2 resins. Resins were dispensed on a 96-well filter plate and antibody sample with different protein concentration was loaded to evaluate resins affinity and static binding capacity. MabSelect Sure, an agarose based matrix with alkaline resistance Protein-A ligand and ProSep-vA Ultra that is a rigid pore glass resin exhibit the highest static binding capacity at ~60-63 mg IgG mL-1 of resin. The two novel resins, GF1 and GF2 show moderate binding capacity at ~28-34 mg IgG mL-1 of resin. By addition of salts during binding, the capacity of the novel resins was enhanced to ~33-42 mg IgG mL-1 resin. Affinity of all evaluated resins was quite comparable. Few other factors for resin selection such as dynamic binding capacity, ligand stability and resistance including resin cost will be briefly discussed.
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