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Mechanics of Twisted DNA Molecule Adsorbed on a Biological Membrane

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Open Journal of Biophysics 2020年第3期10卷 129-149页

作者： Radouane El Kinani Hamid Kaidi noureddine Barka Departement of Mathematics Computer Science and Engineering University of Quebec at Rimouski Rimouski Canada Laboratory of Scientific Research and Pedagogical Development CRMEF Meknes Morocco

DNA is the carrier of all cellular genetic information and increasingly used in nanotechnology. The study of DNA molecule achieved in vitro while submitting the DNA to all chemicals agent capabilities to destabilize links hydrogen, such as pH, temperature. In fact, the DNA enveloped in the membrane cellular, so it is legitimate to study the influence of membrane undulations. In this work, we try to show that the fluctuations of the membrane can be considerate as a physics agent is also capable to destabilize links hydrogen. In this investigation, we assume that each pair base formed an angle an with the membrane’s surface. We have proposed a theoretical model, and we have established a relationship between the angle formed by the pair base θeq and an angle formed by the membrane and each pair base. We assume that DNA and biomembrane interact via a realistic potential of Morse type. To this end, use is made of a generalized model that extends that introduced by M. Peyrard and A. R. Bishop in the past modified by M. Zoli. This generalized model is based on the resolution of a Schrödinger-like equation. The exact resolution gives the expression of the ground state, and the associated eigenvalue (energy) that equals the free energy, in the thermodynamic limit. First, we compute the denaturation temperature of DNA strands critical temperature. Second, we deduce all critical properties that mainly depend on the parameters of the model, and we quantify the effects of the membrane undulations. These undulations renormalize all physical quantities, such as harmonic stacking, melting temperature, eigenfunctions, eigenvalues and regular part of specific heat.

关键词： Biomembrane DNA Molecule Denaturation Interactions Critical Properties

Hardness Profile Prediction for a 4340 Steel Spline Shaft Heat Treated by Laser Using a 3D Modeling and Experimental Validation

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Journal of Materials Science and Chemical Engineering 2016年第4期4卷 9-19页

作者： Mahdi Hadhri Abderazzak El Ouafi noureddine Barka Computer Science and Engineering Department University of Quebec Rimouski Canada

Laser surface transformation hardening becomes one of the most effective processes used to improve wear and fatigue resistance of mechanical parts. In this process, the material physicochemical properties and the heating system parameters have significant effects on the characteristics of the hardened surface. To appropriately exploit the benefits presented by the laser surface hardening, it is necessary to develop a comprehensive strategy to control the process variables in order to produce desired hardened surface attributes without being forced to use the traditional and fastidious trial and error procedures. The paper presents a study of hardness profile predictive modeling and experimental validation for spline shafts using a 3D model. The proposed approach is based on thermal and metallurgical simulations, experimental investigations and statistical analysis to build the prediction model. The simulation of the hardening process is carried out using 3D finite element model on commercial software. The model is used to estimate the temperature distribution and the hardness profile attributes for various hardening parameters, such as laser power, shaft rotation speed and scanning speed. The experimental calibration and validation of the model are performed on a 3 kW Nd:Yag laser system using a structured experimental design and confirmed statistical analysis tools. The results reveal that the model can provide not only a consistent and accurate prediction of temperature distribution and hardness profile characteristics under variable hardening parameters and conditions but also a comprehensive and quantitative analysis of process parameters effects. The modelling results show a great concordance between predicted and measured values for the dimensions of hardened zones.

关键词： Heat Treatment Laser Surface Transformation Hardening Finite Element Method Hardness Profile Prediction AISI 4340 Nd:Yag Laser System ANOVA

Techniques of Transmitting Beamforming to Control the Generated Weights

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International Journal of Communications, Network and System Sciences 2010年第7期3卷 612-619页

作者： Imen Sfaihi noureddine Hamdi Ammar Bouallegue 不详

In this paper, we consider the limited feedback Transmitting Beamforming for MISO systems. In conventional techniques, all vectors of a large codebook (CB), used for the feedback of the quantized channel state information (CSI), are broadcasted to all users, in a guard period which is followed by data burst periods. Instead of transmitting a high number of codevectors, we thought to divide the CB into several sub-codebooks (SC) and the broadcast would be based on the switch between them. Accordingly, a good performance can be provided while minimizing the required feedback channel capacity applying some proposed techniques such as “the switched Sub Codebook (SSC)” and “the Fairness SSC (FSSC)”. To minimize the quantization error, we propose two other techniques. The first is based on making Transmit SSC vectors controlled by a rotation weight (RW) to obtain almost a zero correlation between the SSC vectors used for the selected spatial channels. The second is based on introducing “the Schmidt algorithm” to construct an orthonormal weights using the generated weights. These two proposed techniques increase the probability of the selection of the worst case user on his best codevector to make zero the angle between his couple codevector and channel response. To analyze and validate the performance of these proposed techniques, simulation results are presented.

关键词： MISO Beamforming Limited Feedback CSI SSC FSSC RW-FSSC SSC-Schmidt Algorithm

Theoretical Simulation of the Infrared Absorption Spectrum of the Strong Hydrogen and Deuterium Bond in 2-Pyridone Dimer

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Open Journal of Physical Chemistry 2012年第4期2卷 228-239页

作者： noureddine Issaoui Houcine Ghalla Brahim Oujia Quantum Physics Laboratory Sciences Faculty of Monastir Monastir Tunisia

This work presents a theoretical simulation of the infrared spectra of strong hydrogen bond in alpha-phase 2-pyridone dimers, as well as in their deuterium derivatives at room temperature. The theory takes into account an adiabatic anharmonic coupling between the high-frequency N-H(D) stretching and the low-frequency intermolecular N...O stretching modes by considering that the effective angular frequency of the fast mode N-H(D) is assumed to be strongly dependent on the slow mode stretching coordinate N...O, the intrinsic anharmonicity of the low-frequency N...O mode through a Morse potential, Davydov coupling triggered by resonance exchange between the excited states of the fast modes of the two hydrogen bonds involved in the cyclic dimer, multiple Fermi resonances between the N-H(D) stretching and the overtone of the N-H(D) bending vibrations and the direct and indirect damping of the fast stretching modes of the hydrogen bonds and of the bending modes. The IR spectral density is computed within the linear response theory by Fourier transform of the autocorrelation function of the transition dipole moment operator of the N-H(D) bond. The theoretical line shapes of the υN-H(D) band of alpha-phase 2-pyridone dimers are compared to the experimental ones. The effect of deuteration is successfully reproduced.

关键词： Strong Hydrogen Bound Alpha-Phase 2-Pyridone Dimer Infrared Spectral Density Davydov Coupling Morse Potential Fermi Resonances

Experimental Study on Diflubenzuron: Degradation in Freshwater and Bioconcentration in Mosquitofish Following Chronic Exposure

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Journal of Environmental Protection 2013年第2期4卷 188-194页

作者： Nedjoua Zaidi Jean-Pierre Farine noureddine Soltani Centre des Sciences du Gout et de l’Alimentation Centre National de la Recherche Scientifique-Unité Mixte de Recherche Faculté des Sciences Université de Bourgogne Dijon France Laboratory of Applied Animal Biology Department of Biology Faculty of Sciences Badji Mokhtar University of Annaba Annaba Algeria

Diflubenzuron (DFB, trade name dimilin 25 WP) is a chitin synthesis inhibitor widely used against forest insect pests in Algeria. Prior to implementation of these products as chemical agents for mosquito control, knowledge on their potential effects on non-target organisms and its behaviour in water are needed. Therefore, the present study was focused on DFB and aimed to use an HPLC procedure developed previously in order to obtain information on its degradation in freshwater and its bioconcentration in adult females of the fish Gambusia affinis (Cyprinodondiformes, Poeciliidae), which is one of the best candidates for biological control programs against mosquitoes. The adult females were exposed to dimilin (initial concentration 312 ng a.i./ml) for 28 days and residues analysis determined at different exposure times (0, 7, 14, 21 and 28 days). The concentration of DFB in freshwater decreased with exposure time while the amount of residues detected at the surface of the fish body increased progressively to reach a maximum at day 14 (162.7 ± 14.0 ng/fish) and declined thereafter during the exposure period. In addition, DFB incorporation into body increased with decreasing DFB concentration in water at each exposure time. The following average distribution was noted at the end of experiment (28 days): about 33% of the applied concentration was detected on the surface of fish body and was recovered by simple rinsing, and about 67% was found inside the fish body. A degradation in water and surface of fish occurred starting day 14 during the experimental period. Thus, about 40% of the initial concentration was degraded in freshwater after 28 days. The results are discussed to develop a better understanding of the degradation of dimilin in water and their potential effect on non-target organisms for its application for controlling mosquito.

关键词： Diflubenzuron Dimilin Gambusia Affinis Residues HPLC Degradation Bioconcentration

ANN Based Model for Estimation of Transformation Hardening of AISI 4340 Steel Plate Heat-Treated by Laser

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Materials Sciences and Applications 2015年第11期6卷 978-994页

作者： Guillaume Billaud Abderazzak El Ouafi noureddine Barka Mathematics Computer Science and Engineering Department University of Quebec at Rimouski Rimouski Canada

Quality assessment and prediction becomes one of the most critical requirements for improving reliability, efficiency and safety of laser surface transformation hardening process (LSTHP). Accurate and efficient model to perform non-destructive quality estimation is an essential part of the assessment. This paper presents a structured and comprehensive approach developed to design an effective artificial neural network (ANN) based model for quality estimation and prediction in LSTHP using a commercial 3 kW Nd:Yag laser. The proposed approach examines laser hardening parameters and conditions known to have an influence on performance characteristics of hardened surface such as hardened bead width (HBW) and hardened depth (HD) and builds a quality prediction model step by step. The modeling procedure begins by examining, through a structured experimental investigations and exhaustive 3D finite element method simulation efforts, the relationships between laser hardening parameters and characteristics of hardened surface and their sensitivity to the process conditions. Using these results and various statistical tools, different quality prediction models are developed and evaluated. The results demonstrate that the ANN based assessment and prediction proposed approach can effectively lead to a consistent model able to accurately and reliably provide an appropriate prediction of hardened surface characteristics under variable hardening parameters and conditions.

关键词： Laser Hardening Process AISI 4340 Steel Case Depth Hardened Bead Width Artificial Neural Network

A Predictive Modeling Based on Regression and Artificial Neural Network Analysis of Laser Transformation Hardening for Cylindrical Steel Workpieces

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Journal of Surface Engineered Materials and Advanced Technology 2016年第4期6卷 149-163页

作者： Ahmed Ghazi Jerniti Abderazzak El Ouafi noureddine Barka Mathematics Computer Science and Engineering Department University of Quebec at Rimouski Rimouski Canada

Laser surface hardening is a very promising hardening process for ferrous alloys where transformations occur during cooling after laser heating in the solid state. The characteristics of the hardened surface depend on the physicochemical properties of the material as well as the heating system parameters. To exploit the benefits presented by the laser hardening process, it is necessary to develop an integrated strategy to control the process parameters in order to produce desired hardened surface attributes without being forced to use the traditional and fastidious trial and error procedures. This study presents a comprehensive modelling approach for predicting the hardened surface physical and geometrical attributes. The laser surface transformation hardening of cylindrical AISI 4340 steel workpieces is modeled using the conventional regression equation method as well as artificial neural network method. The process parameters included in the study are laser power, beam scanning speed, and the workpiece rotational speed. The upper and the lower limits for each parameter are chosen considering the start of the transformation hardening and the maximum hardened zone without surface melting. The resulting models are able to predict the depths representing the maximum hardness zone, the hardness drop zone, and the overheated zone without martensite transformation. Because of its ability to model highly nonlinear problems, the ANN based model presents the best modelling results and can predict the hardness profile with good accuracy.

关键词： Heat Treatment Laser Surface Hardening Hardness Predictive Modeling Regression Analysis Artificial Neural Network Cylindrical Steel Workpieces AISI 4340 Steel Nd:Yag Laser System

Single Track Laser Surface Hardening Model for AISI 4340 Steel Using the Finite Element Method

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Modeling and Numerical Simulation of Material Science 2016年第2期6卷 17-27页

作者： Ahmed Ghazi Jerniti Abderazzak El Ouafi noureddine Barka Computer Science and Engineering Department University of Quebec Rimouski Canada

Laser surface hardening becomes one of the most effective techniques used to enhance wear and fatigue resistance of mechanical parts. The characteristics of the hardened surface depend on the physicochemical properties of the material as well as the heating system parameters. To adequately exploit the benefits presented by the laser heating method, it is necessary to develop a comprehensive strategy to control the process parameters in order to produce desired hardened surface attributes without being forced to use the traditional and fastidious trial and error procedures. This study presents a comprehensive approach used to build a simplified model for predicting the hardness profile. A finite element method based prediction model for AISI 4340 steel is investigated. A circular shape with a Gaussian distribution is used for modeling the laser heat source. COMSOL MULTIPHYSICS software is used to solve the heat transfer equations, estimate the temperature distribution in the part and consequently predict the hardness profile. A commercial 3 kW Nd:Yag laser system is combined to a structured experimental design and confirmed statistical analysis tools for conducting the experimental calibration and validation of the model. The results reveal that the model can effectively lead to a consistent and accurate prediction of the hardness profile characteristics under variable hardening parameters and conditions. The results show great concordance between predicted and measured values for the dimensions of hardened and melted zones.

关键词： Heat Treatment Laser Surface Hardening AISI 4340 Nd:Yag Laser System Finite Element Method Hardness Profile Prediction

Applied the Large Scale Particle Image Velocimetry Technique for Measurement the Velocity of Gravity Currents in the Laboratory

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Journal of Water Resource and Protection 2015年第8期7卷 597-604页

作者： Dhafar Ibrahim Ahmed noureddine Latrache Blaise Nsom Université de Bretagne Occidentale Brest France Faculty of Engineering University of Wassit Kut Iraq

This study includes a series of laboratory experiments for investigated the gravity current of fresh water with density ρ-?ρ, and initial speed u0 upon the free surface of an ambient liquid (salty water) with density ρ at rest in a basin. It’s have been presented to illuminate the dominant flow and transport phenomena in the presence of river, stream and wetland ecology, stream corridor restoration, in the case of accidental pollution spills. The characterized of the local kinematic field, i.e. the local velocity and vorticity fields, the measurement methods include particle image velocimetry (PIV) at the water surface using a technique similar to large scale of particle image velocimetry (LSPIV).

关键词： Gravity Currents Image Processing Large-Scale Particle Image Velocimetry Technique Spatiotemporal Diagrams Technique