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Numerical Investigation of Thermal Behavior of CNC Machine Tool and Its Effects on Dimensional Accuracy of Machined Parts

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Journal of Software Engineering and Applications 2024年第8期17卷 617-637页

作者： Erick Matezo-Ngoma abderrazak El Ouafi Ahmed Chebak Computer Science and Engineering Department University of Quebec Rimouski Canada GTI Mohammed VI Polytechnic University Ben Guerir Morocco

The dimensional accuracy of machined parts is strongly influenced by the thermal behavior of machine tools (MT). Minimizing this influence represents a key objective for any modern manufacturing industry. Thermally induced positioning error compensation remains the most effective and practical method in this context. However, the efficiency of the compensation process depends on the quality of the model used to predict the thermal errors. The model should consistently reflect the relationships between temperature distribution in the MT structure and thermally induced positioning errors. A judicious choice of the number and location of temperature sensitive points to represent heat distribution is a key factor for robust thermal error modeling. Therefore, in this paper, the temperature sensitive points are selected following a structured thermomechanical analysis carried out to evaluate the effects of various temperature gradients on MT structure deformation intensity. The MT thermal behavior is first modeled using finite element method and validated by various experimentally measured temperature fields using temperature sensors and thermal imaging. MT Thermal behavior validation shows a maximum error of less than 10% when comparing the numerical estimations with the experimental results even under changing operation conditions. The numerical model is used through several series of simulations carried out using varied working condition to explore possible relationships between temperature distribution and thermal deformation characteristics to select the most appropriate temperature sensitive points that will be considered for building an empirical prediction model for thermal errors as function of MT thermal state. Validation tests achieved using an artificial neural network based simplified model confirmed the efficiency of the proposed temperature sensitive points allowing the prediction of the thermally induced errors with an accuracy greater than 90%.

关键词： CNC Machine Tool Dimensional Accuracy Thermal Errors Error Modelling Numerical Simulation Finite Element Method Artificial Neural Network Error Compensation

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A Glassy Carbon Electrode Modified with Cellulose Nanofibrils from Ammophila arenaria for the Sensitive Detection of L-Trytophan

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Journal of Sensor Technology 2024年第3期14卷 35-50页

作者： Sondes Bourigua Feriel Boussema Zayneb Jebali Houcine Barhoumi Hatem Majdoub abderrazak Maaref Nicole Jaffrezic-Renault Laboratory of Advanced Materials and Interfaces Faculty of Sciences University of Monastir Monastir Tunisia Institute of Analytical Sciences University of Lyon Villeurbanne France

L-tryptophan is an essential amino acid for human health. Nanofibrillated cellulose (NFC) from marram grass (Ammophila arenaria) extracted from plants harvested in the center of Tunisia was used for the first time for the modification of a glassy carbon electrode (GCE), for the sensitive detection of L-tryptophan (Trp). After spectroscopic and morphological characterization of the extracted NFC, the GC electrode modification was monitored through cyclic voltammetry. The NFC-modified electrode exhibited good analytical performance in detecting Trp with a wide linear range between 7.5 × 10−4 mM and 10−2 mM, a detection limit of 0.2 µM, and a high sensitivity of 140.0 µA∙mM−1. Additionally, the NFC/GCE showed a good reproducibility, good selectivity versus other amino acids, uric acid, ascorbic acid, and good applicability to the detection of Trp in urine samples.

关键词： Nanofibrillated Cellulose Chitosan Chemically Modified Glassy Carbon Electrode Electrochemical Detection L-Tryptophan

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Water erosion risk mapping using derived parameters from digital elevation model and remotely sensed data

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Geo-Spatial Information Science 2012年第3期15卷 157-169页

作者： Soufiane MAIMOUNI abderrazak EL-HARTI abderrazak BANNARI El-Mostafa BACHAOUI Remote Sensing and Geographical Information Systems Laboratory Faculty of Science and TechniquesUniversity of Sultan Moulay SlimaneBeniMellalMorocco Remote Sensing and Geomatics of the Environment Laboratory Department of GeographyUniversity of OttawaOntarioCanada

The aim of this study is to map the areas exposed to water erosion risks in the High Atlas Mountains of Morocco around the Hassan-I *** methodology is based on the analysis of the water power index(WPI)as a hydrological parameter,the vegetation cover,and the litho-logical *** WPI was derived from a Digital Elevation Model(DEM)and the litho-logical units and vegetation cover were derived from Advanced Land Imager sensor on the Earth Observing-1 satellite *** image was corrected from radiometric and atmospheric effects,and geometrically rectified using a DEM and grounds control *** variables were integrated in a Geographical Information Systems environment,and Multi-Criteria Analyses were used to derive the water erosion risks map pointing out the most exposed areas requiring the implementation of suitable conservation *** validation of the obtained results shows the simplicity and the potential of this approach for water erosion risks mapping.

关键词： water erosion risks GIS remote sensing vegetation cover litho-logical units hydrological parameter

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Efficient fall activity recognition by combining shape and motion features

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Computational Visual Media 2020年第3期6卷 247-263页

作者： abderrazak Iazzi Mohammed Rziza Rachid Oulad Haj Thami LRIT RABAT IT CENTERFaculty of SciencesUniversity of Mohammed 5 in RabatMorocco ADMIR LAB IRDARABAT IT CENTERENSIASUniversity of Mohammed 5 in RabatMorocco

This paper presents a vision-based system for recognizing when elderly adults fall.A fall is characterized by shape deformation and high *** represent shape variation using three features,the aspect ratio of the bounding box,the orientation of an ellipse representing the body,and the aspect ratio of the projection *** motion variation,we extract several features from three blocks corresponding to the head,center of the body,and feet using optical *** each block,we compute the speed and the direction of *** activity is represented by a feature vector constructed from variations in shape and motion features for a set of frames.A support vector machine is used to classify fall and non-fall *** on three different datasets show the effectiveness of our proposed method.

关键词： shape motion features

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Backgating effect in GaAs FETs with a channel–semi-insulating substrate boundary

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Journal of Semiconductors 2014年第3期35卷 33-38页

作者： Ahmed Chaouki Megherbi Said Benramache abderrazak Guettaf Electrical Engineering Department Faculty of Technology University of Biskra Material Sciences Department Faculty of Sciences University of Biskra

This study focuses on modeling the effects of deep hole traps, mainly the effect of the substrate（backgating effect） in a GaAs transistor MESFT. This effect is explained by the existence, at the interface, of a space charge zone. Any modulation in this area leads to response levels trapping the holes therein to the operating temperature. We subsequently developed a model treating the channel substrate interface as an N–P junction, allowing us to deduce the time dependence of the component parameters of the total resistance R ds, the pinch-off voltage V P, channel resistance, fully open R co and the parasitic series resistance R S to bind the effect trap holes H1and H0. When compared with the experimental results, the values of the R DS（t S/ model for both traps show that there is an agreement between theory and experiment; it has inferred parameter traps, namely the density and the time constant of the trap. This means that a space charge region exists at the channel–substrate interface and that the properties can be approximated to an N–P junction.

关键词： traps pinch-off voltage resistance channel substrate interface

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Local model networks based mixed-sensitivity H-infinity control of CE-150 helicopters

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Control Theory and Technology 2017年第1期15卷 34-44页

作者： Mohamed Redouane KAFI Hicham CHAOUI Suruz MIAH abderrazak DEBILOU Laboratoire de G~nie Electrique (LAGE) Universite Kasdi Merbah Ouargla Ouargla Algeria Center for Manufacturing Research Department of ECE Tennessee Technological University Cookeville TN U.S.A. Department of Electrical and Computer Engineering Bradley University Peoria IL U.S.A. Faculty of Sciences Department of Electronics Biskra University Algeria

In this paper, a local model network H-infinity control is proposed for CE-150 helicopter stabilization. The proposed strategy capitalizes on recent developments on H-infinity control and its promising results in robust stabilization of plants under unstructured uncertainties. CE-150 helicopters are known for their varying operating conditions along with external disturbances. Therefore, local model networks are introduced for their adaptive feature and since they provide a powerful combination of fuzzy logic and conventional linear control techniques to control nonlinear systems without the added computational burden of soft-computing techniques. Using the fact that the system can be linearized at different operating points, a mixed sensitivity H-infinity controller is designed for the linearized system, and combined within a network to make transitions between them. The proposed control structure ensures robustness, decoupling of the system dynamics while achieving good performance. A comparison is carried-out against the well-known proportional-integral-derivative （PID） control technique. Results are presented to illustrate the controller＇s performance in various operating conditions.

关键词： H-infinity control helicopter local model network robust stabilization

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Correlation between electrical conductivity–optical band gap energy and precursor molarities ultrasonic spray deposition of ZnO thin films

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Journal of Semiconductors 2013年第11期34卷 15-19页

作者： Said Benramache Okba Belahssen abderrazak Guettaf Ali Arif Material Sciences Laboratory Faculty of Science University of Biskra Physic Laboratory of Thin Films and Applications LPCMA University of Biskra Department of Electrical Faculty of Technology University of Biskra

ZnO thin films were deposited using the simple, flexible and cost-effective spray ultrasonic technique at different precursor molarities values. The films were deposited on a glass substrate at 350℃. This paper is to present a new approach to the description of correlation between electrical conductivity and optical gap energy with precursor molarity of ZnO thin films. The ZnO films exhibit higher electrical n-type semiconductors, whose band gap energy increased from 3.08 to 3.37 eV with an increasing of precursor molarity of 0.05 to 0.1 M. The maximum value of electrical conductivity of the films is 7.96 （***）-1 obtained in the ZnO thin film for precursor molarity 0.125 M. The correlation between the electrical and the optical properties with the precursor molarity suggests that the electrical conductivity of the films is predominantly influenced by the band gap energy and the precursor molarity. The measurement of the electrical conductivity of the films with correlation is equal to the experimental with the error is about 1% in the higher conductivity.

关键词： ZnO thin films correlation electrical conductivity, ultrasonic spray technique

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Numerical Modelling of the Transient Hygroscopic Behavior of Flax-Epoxy Composite

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Journal of Renewable Materials 2019年第9期7卷 839-853页

作者： Wajdi Zouari Mustapha Assarar abderrazak Chilali Rezak Ayad Hocine Kebir Universitéde Reims Champagne-Ardenne ITheMM EA 754851097ReimsFrance Ecole Nationale Préparatoire aux Etudes d’Ingéniorat 16012RouïbaAlgeria Sorbonne Universités Universitéde Technologie de CompiègneLaboratoire Roberval(UMR 7337)60205CompiègneFrance

This contribution deals with the development of a three-node triangular plane finite element to analyze the transient hygroscopic behavior of 2/2 twill flax fabric-reinforced epoxy *** plates of this material were fabricated using the vacuum infusion process and composite specimens were then cut and aged in tap water at room temperature until *** simplify,a plane modelling of water diffusion in the aged specimens is adopted and Fick’s model is used to describe the water diffusion *** highlight the heterogeneity of the flax-epoxy samples,the twill flax fabrics waviness is modelled with a sinusoidal *** particular,we show that the proposed finite element formulation allows estimating the flax fiber radial diffusion coefficient by an inverse approach.

关键词： Flax-epoxy composite water ageing fick’s model finite element analysis

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Magnetocaloric Effect in Anisotropic Mixed Spin1/2–1 System: Pair Approximation Method

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Communications in Theoretical Physics 2019年第11期71卷 1370-1378页

作者： abderrazak Boubekri Moulay Youssef El Hafidi Mohamed El Hafidi Laboratory of Condensed Matter Physics Faculty of Sciences Ben M’sik Hassan II University of Casablanca

We use the Pair Approximation method to analyze the magnetic and magnetocaloric behaviors of diluted mixed spin SA=1 and spin SB=1/2 with the anisotropic Heisenberg model, on a cubic lattice with coordination number z=6. Our system is described in presence of an external magnetic field;the phase diagram and thermodynamic properties related to the concentration of magnetic atom(A or B) and the single ion anisotropy are constructed and *** attention is paid to magnetocaloric properties provided by isothermal entropy change as well as the cooling capacity. These cooling power keys are plotted and discussed as a function of interaction anisotropy and magnetic component concentration of two sublattices ions A and B. Numerical results show a double peak structure in the entropy change curve and the inverse magnetocaloric effect related to the presence of the negative single-ion anisotropy.

关键词： anisotropic Heisenberg model dilution entropy change mixed spin system inverse magnetocaloric effect pair approximation magnetic Gruneisen ratio

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Learning-Based Metaheuristic Approach for Home Healthcare Optimization Problem

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Computer Systems Science & Engineering 2023年第4期45卷 1-19页

作者： Mariem Belhor Adnen El-Amraoui abderrazak Jemai François Delmotte Univ.Artois LGI2A LaboratoryUR 3926Technoparc FUTURA 62400BéthuneFrance Univ.Carthage SERCOM LaboratoryEPTMarsa2078Tunisia Univ.Manouba National School of Computer ScienceManouba2010Tunisia

This research focuses on the home health care optimization problem that involves staff routing and scheduling *** considered problem is an extension of multiple travelling salesman *** consists of finding the shortest path for a set of caregivers visiting a set of patients at their homes in order to perform various tasks during a given ***,a mixed-integer linear programming model is proposed to minimize the overall service time performed by all caregivers while respecting the workload balancing ***,when the time horizon become large,practical-sized instances become very difficult to solve in a reasonable computational ***,a new Learning Genetic Algorithm for mTSP(LGA-mTSP)is proposed to solve the ***-mTSP is composed of a new genetic algorithm for mTSP,combined with a learning approach,called learning *** refers to that caregivers’productivity increases as they gain more *** curves approach is considered as a way to save time and *** results show the efficiency of the proposed approach and the impact of learning curve strategy to reduce service times.

关键词： Home healthcare scheduling and routing problem optimization multiple travelling salesman problem learning curves genetic algorithm

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