排序方式: 共有26条查询结果,搜索用时 15 毫秒
1.
A. Benhamida I. Djeran-Maigre H. Dumontet S. Smaoui 《International Journal of Rock Mechanics and Mining Sciences》2005,42(7-8):996-1005
The modelling of hydromechanical behavior of clayey sediments by homogenization theory is described. The rheological model of clays buried in depth requires a three-dimensional approach and laboratory experiments to quantify the model parameters. An iterative process which can be coupled to any homogenization method is used to model the porous media behavior. Hydromechanical compaction results from oedometric experiments are simulated with the proposed model. 相似文献
2.
Moez Smaoui Zoubeir Bouaziz Ali Zghal Gilles Dessein Maher Baili 《The International Journal of Advanced Manufacturing Technology》2011,56(5-8):463-474
Since industry is rapidly developing, either locally or globally, manufacturers witness harder challenges due to the growing competitivity. This urges them to better consider the four factors linked to production and output: quality, quantity, cost and price, quality being of course the most important factor which constitutes their main concern. Efforts will be concentrated??in this research??on improving the quality and securing more accuracy for a machined surface in ball-end milling. Quality and precision are two essential criteria in industrial milling. However, milling errors and imperfections, due mainly to the cutting tool deflection, hinder the full achieving of these targets. Our task, all along this paper, consists in studying and realizing the simulation of the deflected cutting tool trajectory, by using the methods which are available. In a future stage, and in the frame of a deeper research, the simulation process will help to carry out the correction and the compensation of the errors resulting from the tool deflection. The corrected trajectory which is obtained by the method mirror will be sent to the machine. To achieve this goal, the next process consists??as a first step??in selecting a model of cutting forces for a ball-end mill. This allows to define??later on??the behavior of this tool, and the emergence of three methods namely the analytical model, the finite elements method, and the experimental method. It is possible to tackle the cutting forces simulation, all along the tool trajectory, while this latter is carrying out the sweeping of the part to be machined in milling and taking into consideration the cutting conditions, as well as the geography of the workpiece. A simulation of the deflected cutting tool trajectory dependent on the cutting forces has been realized. 相似文献
3.
Ikram Smaoui Faouzi Zarai Mohammad M. Banat Lotfi Kamoun 《Wireless Personal Communications》2010,54(3):417-445
Vertical handoff is one of the most important issues for the next generation heterogeneous wireless networks. However, in
many situations, unbeneficial vertical handoffs occur across intersystem heterogeneous networks cause network performance
degradation. Therefore, we propose a novel configuration architecture that can be deployed in the next generation of wireless
networks. Second, we propose a predictive and adaptive Vertical Handoff Decision Scheme that optimizes the handoff initiation
time as well as selection of the most optimal network. The proposed vertical handoff decision algorithm considers the technology
type as well as the Signal to Interference Ratio (SIR), the Mobile Station (MS) velocity, the user preferences, the applications
requirements and the terminal capabilities as the most important factors to make vertical handoff decision. In order to minimize
handoff costs, the proposed decision algorithm uses the dwell timer concept. The handoff costs are analyzed in terms of unnecessary
and unbeneficial handoffs rate.The simulation results show that the reduction of unnecessary handoffs proposed in our vertical
handoff decision scheme reduces the handoff blocking probability, the packets loss rate and the handoff overhead 相似文献
4.
H. Smaoui L. A. Schmit 《International journal for numerical methods in engineering》1988,26(3):555-570
An integrated approach to the minimum weight design of geometrically non-linear three dimensional truss structures with geometric imperfections, subject to inequality constraints on static displacements, stresses, local buckling and cross sectional areas, is investigated. The integrated structural synthesis problem involves design and response quantities as independent variables and equilibrium equations, describing the finite element model, as equality constraints. The non-linear structural analysis and the optimization are thus merged together into a single process. A computer program developed to compute the contraint values and analytical gradients is coupled with a generalized reduced gradient algorithm to solve the integrated problem. Numerical results for a geometrically non-linear shallow dome example problem are presented for various types of imperfections. Furthermore, it is found that the algorithm is capable of detecting and guarding against system as well as element elastic instability using equilibrium information only, that is, without imposing system and local buckling inequality constraints. 相似文献
5.
Increasing the concrete alkali content from 0.6% to 1.25% of Na2Oe of the cement mass by adding NaOH to the mixture water has harmful effects on most mechanical properties (compressive, splitting, direct tensile, and flexure strengths) of concrete made with a water-to-cement (w/c) ratio of 0.41 and limestone aggregates not susceptible to alkali-silica reaction (ASR), however not on the elasticity modulus measured under compression or direct tension. Shrinkage tests at 50% RH and 23 °C started after 7 days at 100% RH and 23 °C show that the low-alkali concrete shrinks more than the high-alkali one, despite similar water losses. Freeze-thaw tests performed on air-entrained concretes show that the two concretes resist well to freezing and thawing while showing similar air-void systems. When examined under the scanning electron microscope (SEM), the hydrates in the two concretes present similar microstructure; however, the high-alkali concrete shows a more reticular and porous microtexture, which could explain the reduction in strength. 相似文献
6.
Mariam Fourati Slim Smaoui Hajer Ben Hlima Karim Ennouri Ahlem Chakchouk Mtibaa Imen Sellem Khaoula Elhadef Lotfi Mellouli 《International Journal of Food Science & Technology》2020,55(3):1080-1087
Microbiological, chemical and sensory effects of pomegranate peel ethanol extract (EE) at 0.1, 0.5 and 1% (w w−1) on refrigerated minced beef meat were undertaken. Chemical analyses revealed that the treated meat underwent significant decrease (P < 0.05) of primary and secondary lipid oxidation. By the end of storage, EE at 1% reduced the MetMb, carbonyl group accumulation and the disappearance of sulphydryl proteins by 56.68, 65.71 and 59.69% respectively, compared with control samples. EE at 1% showed also the highest scores for colour, appearance, odour and overall acceptability (OA) attributes using a 9-point hedonic scale. Chemometric approaches showed that lipid/protein oxidation analysis, sensory attributes and storage time allowed the samples discrimination. Oxidative stability parameters were equally used to predict OA by linear regression analysis. The reported data provide an approach to strengthen the interpretation of sensory quality and how they are affected by chemical changes in newly formulated meat products. 相似文献
7.
Slim Smaoui Karim Ennouri Ahlem Chakchouk-Mtibaa Ines Karray-Rebai Maher Hmidi Kameleddine Bouchaala Lotfi Mellouli 《Food and Bioprocess Technology》2017,10(9):1655-1667
In this study, bacteriocin “BacTN635” was used to maintain quality and extend shelf life of refrigerated turkey meat sausage. Connections between lipid and protein oxidations and instrumentally textural changes using Bayesian networks during storage of turkey meat sausage were also studied. BacTN635 slowed down metmyoglobin and carbonyl group accumulation and delayed the disappearance of sulphydryl proteins (P < 0.05) in turkey meat sausage. This bacteriocin led to a decrease in primary and secondary lipid oxidation (P < 0.05) and enhanced texture characteristics of sausage by reducing hardness (P < 0.05) and controlling the elasticity lose during refrigeration. We have also investigated the correlations between protein and lipid oxidation and instrumentally measured the parameters of turkey meat sausage treated by BacTN635. The developed model, based on Bayesian network techniques, can automatically learn emerging models in data to explain protein and lipid oxidation and texture modification relationships. Equally, sensorial parameters were used for constructing regression models to predict overall acceptability. In conclusion, BacTN635 could be a promising tool for extending the safety and quality of refrigerated turkey meat sausage. This bacteriocin could be a strong candidate for future applications in a wide range of meat products. 相似文献
8.
Hichem Smaoui Nissaf Mzabi Hajer Guermazi Youssef Mlik Serge Agnel Alain Toureille François Schué 《Polymer International》2007,56(3):325-332
The performance of insulators is usually affected by the presence of space charges. The evolution of these charges under applied constraints in many cases leads to the degradation of these materials. To evaluate the performance of an insulator it is necessary to study the evolution of the physical and chemical properties in the presence of space charges. In this paper, the effect of gamma irradiation on the space charge behaviour in polyetherimide (PEI; Ultem 1000) has been investigated at different radiation doses. Space charge measurements were made using thermally stimulated currents. Infrared spectroscopy characterisation was performed to investigate the effect of gamma irradiation on the physicochemical properties of PEI. The results obtained show minor differences in the infrared spectra, mainly in the 410 cm?1 region. It is found that irradiation leads to a few structural changes in the material. The thermostimulated depolarisation current (TSDC) results show that β relaxations in PEI are affected by gamma irradiation. The activation energies of dipoles were calculated from the TSDC curves. Copyright © 2006 Society of Chemical Industry 相似文献
9.
Higher order sliding mode control based on optimal approach of an electropneumatic actuator 总被引:1,自引:0,他引:1
This paper presents the synthesis and the experimental implementation of robust higher order sliding mode controllers for an electropneumatic actuator. These controllers are based on a recent approach and are designed in monovariable (position control) and multivariable (position and pressure control) contexts. The controllers' robustness is analysed with respect to parameters uncertainties and load disturbances. 相似文献
10.
Laifa Israa Hajji Mounir Farhat Nèjia Elkhouni Amine Smaoui Abderrazak M’nif Adel Hamzaoui Ahmed Hichem Savouré Arnould Abdelly Chedly Zorrig Walid 《SILICON》2021,13(12):4501-4517
Silicon - Silicon (Si) plays an important role in providing beneficial effects on plant growth and yield, especially under stressful environments such as salinity. The objective of this work is to... 相似文献