Designing of a new seismic base isolation system

The design of a new base isolation system is proposed in this research with the objective that the system does not transmit any force to the structure under horizontal loading. The structure must remain operational and steady. Before investigating the dynamics problem of the base isolation system, the isolator components of the model can be solved analytically using different approaches. In order to calculate the deformation of any element of the isolator due to a compressive vertical load, the analysis focuses on the primary instability region to determine all deformations parameters which can lead to frictions coefficients. This region is located at the interaction contact point between the elements. The design is based on the contact point developed by different approaches. In the present study, the mathematical analysis methods by using formulations can calculate the different dimensions and deformations of the elements of the system and which are verified using ANSYS finite element analysis.  After ensuring the adequate dimensions of the different parts of the isolator system from the analysis, the system can be applied on the structure. This technique can reduce significantly the displacements and accelerations at the underground level with a new seismic isolation system, which it is an uncoupled system between the structure and the underground

Designing of a new seismic base isolation system

The design of a new base isolation system is proposed in this research with the objective that the system does not transmit any force to the structure under horizontal loading. The structure must remain operational and steady. Before investigating the dynamics problem of the base isolation system, the isolator components of the model can be solved analytically using different approaches. In order to calculate the deformation of any element of the isolator due to a compressive vertical load, the analysis focuses on the primary instability region to determine all deformations parameters which can lead to frictions coefficients. This region is located at the interaction contact point between the elements. The design is based on the contact point developed by different approaches. In the present study, the mathematical analysis methods by using formulations can calculate the different dimensions and deformations of the elements of the system and which are verified using ANSYS finite element analysis.  After ensuring the adequate dimensions of the different parts of the isolator system from the analysis, the system can be applied on the structure. This technique can reduce significantly the displacements and accelerations at the underground level with a new seismic isolation system, which it is an uncoupled system between the structure and the underground

Implementation of the One Health approach to fight arbovirus infections in the Mediterranean and Black Sea Region: Assessing integrated surveillance in Serbia, Tunisia and Georgia

Background In the Mediterranean and Black Sea Region, arbovirus infections are emerging infectious diseases. Their surveillance can benefit from one health inter-sectoral collaboration; however, no standardized methodology exists to study One Health surveillance. Methods We designed a situation analysis study to document how integration of laboratory/clinical human, animal and entomological surveillance of arboviruses was being implemented in the Region. We applied a framework designed to assess three levels of integration: policy/institutional, data collection/data analysis and dissemination. We tested the use of Business Process Modelling Notation (BPMN) to graphically present evidence of inter-sectoral integration. Results Serbia, Tunisia and Georgia participated in the study. West Nile Virus surveillance was analysed in Serbia and Tunisia, Crimea-Congo Haemorrhagic Fever surveillance in Georgia. Our framework enabled a standardized analysis of One Health surveillance integration, and BPMN was easily understandable and conducive to detailed discussions among different actors/institutions. In all countries, we observed integration across sectors and levels except in data collection and data analysis. Data collection was interoperable only in Georgia without integrated analysis. In all countries, surveillance was mainly oriented towards outbreak response, triggered by an index human case. Discussion The three surveillance systems we observed prove that integrated surveillance can be operationalized with a diverse spectrum of options. However, in all countries, the integrated use of data for early warning and inter-sectoral priority setting is pioneeristic. We also noted that early warning before human case occurrence is recurrently not operationally prioritized

Deux précurseurs de la bibliologie en terre d'Islam

L'article qui suit est issu de deux communications de MM. Mohamed Rebhi et Wahid Gdoura présentées au IXe colloque international de bibliologie qui s'est tenu à Tunis sous la présidence de Robert Estivals les 21-24 mars 1990. Dans la première (« Le milieu socio-culturel et la matière documentaire d'Ibn an-Nadim, précurseur de la bio-bibliographie arabe »), M. Rebhi montre comment, dès le début de l'islam, la science du livre, qui devient rapidement la science de l'écrit, occupe une place prééminente dans le contexte de l'épanouissement culturel qui prévaut à cette époque. L'œuvre bio-bibliographique de Ibn an-Nadim démontre alors un modernisme et une rigueur scientifique étonnants. Dans la deuxième communication, « La conception de la bibliologie chez al-Kalkashandi », W. Gdoura, maître- assistant à l'Institut supérieur de documentation à l'université de Tunis-1, nous présente les travaux de cet auteur dont la réflexion bibliologique et les schémas de classification restent d'actualité.Rebhi Mohamed, Odoura Wahid. Deux précurseurs de la bibliologie en terre d'Islam. In: Communication et langages, n°86, 4ème trimestre 1990. pp. 5-21

Hysteresis and Bistability Bifurcation Induced by Combined Fluid Shear Thickening and Double-Diffusive Convection in Shallow Porous Enclosures Filled with Non-Newtonian Power-Law Fluids

This paper presents a numerical study of the linear and non-linear stability of thermosolutal convection within a porous medium saturated by a non-Newtonian binary fluid. The power-law model is utilized for modeling the behavior of the working medium. The given statement implies that the horizontal boundaries experience thermal and solutal flow rates, whereas the vertical walls are impermeable and thermally isolated. The relevant factors that govern the problem being investigated are the Rayleigh number, , the power-law index, , the cavity aspect ratio, , the Lewis number, , and the buoyancy ratio, . An analytical solution is obtained for shallow enclosures ( ) using the parallel flow approximation and a modified form of the Darcy equation. By solving the entire set of governing equations, a numerical investigation of the same phenomenon was conducted. One of the most intriguing discoveries from this research is that it identifies a bi-stability phenomenon, this particular phenomenon signifies the existence of two stable solutions. The results obtained from both methods demonstrate a good level of agreement across a diverse range of these governing parameters

Effets du désaccord de phase sur la dynamique non-linéaire d'un oscillateur photoréfractif à conjugaison de phase

La problématique principale de ce travail est l'analyse du désaccord entre le modèle théorique de l'oscillateur semi-linéaire utilisé jusqu'alors dans la littérature et l'observation expérimentale d'oscillation à deux fréquences. La cavité de l'oscillateur photoréfractif semi-linéaire est formée d'un miroir à conjugaison de phase et d'un miroir classique. Une oscillation à deux fréquences est théoriquement prévue pour des forces de couplage nettement supérieures à celles mises en jeu dans l'expérience. Pourtant ce régime d'oscillation est observé de manière reproductible. Pour avoir une vue générale des dynamiques de l'oscillateur, nous avons forcé ce dernier en imposant par effet Doppler une fréquence supplémentaire dans la cavité. Nous avons ainsi étudié les composantes fréquentielles de l'oscillation en fonction de l'excitation Doppler. Cette étude a révélé une rupture de symétrie non prévue par la théorie. Alors pour briser la symétrie dans le modèle, nous avons introduit un nouveau paramètre : le désaccord de phase. Grâce à cette amélioration, nous avons montré qu un désaccord de phase peut réduire considérablement le seuil de l oscillation à deux fréquences à des valeurs voisines de celles mises en jeu dans nos expériences. Nous avons ainsi obtenu un accord satisfaisant entre le modèle et l observation. De plus, l analyse au seuil a permis de mieux comprendre la nature de l oscillation à deux fréquences et d établir le lien avec un phénomène apparemment distinct : l oscillation sans miroir. L oscillation à deux fréquences apparaît dans certaines conditions comme une perturbation de l oscillation sans miroir par la présence du miroir de fond de cavité.The main topic of this dissertation is the analysis of the discrepancy between the predictions of the usual model of the semi-linear oscillator and the observation of a two frequency oscillation. The cavity of the photorefractive semi-linear oscillator is formed by a phase conjugate mirror and a conventional mirror. Although the two frequencies oscillation is theoretically not allowed for the experimental measured values of the coupling strength, this regime of oscillation often develops in the experiment. To acquire a global vision of the oscillator s dynamics, we forced the oscillator by imposing a supplementary frequency in the cavity by Doppler effect. Thus, we studied the frequency components of the oscillation as a function of the excitation. This study revealed a breaking of symmetry that is not predicted by the model. Consequently, to break the symmetry in the model we introduced a new parameter: the phase mismatch. Using this extension, we show that a phase mismatch, induced by a very small misalignment of the pump waves, can reduce the threshold of the two frequency oscillation to values near the ones existing in the experiment. We have thus obtained a satisfying match between the model and the observation. Furthermore, the threshold analysis led to a better understanding of the nature of the two frequency oscillation and showed its closeness to an apparently different phenomenon: the mirrorless oscillation. The two frequency oscillation appears under certain conditions as a perturbation of the mirrorless oscillation by the feedback mirror.DIJON-BU Sciences Economie (212312102) / SudocSudocFranceF

Continuous Stability TS Fuzzy Systems Novel Frame Controlled by a Discrete Approach and Based on SOS Methodology

Generally, the continuous and discrete TS fuzzy systems’ control is studied independently. Unlike the discrete systems, stability results for the continuous systems suffer from conservatism because it is still quite difficult to apply non-quadratic Lyapunov functions, something which is much easier for the discrete systems. In this paper and in order to obtain new results for the continuous case, we proposed to connect the continuous with the discrete cases and then check the stability of the continuous TS fuzzy systems by means of the discrete design approach. To this end, a novel frame was proposed using the sum of square approach (SOS) to check the stability of the continuous Takagi Sugeno (TS) fuzzy models based on the discrete controller. Indeed, the control of the continuous TS fuzzy models is ensured by the discrete gains obtained from the Euler discrete form and based on the non-quadratic Lyapunov function. The simulation examples applied for various models, by modifying the order of the Euler discrete fuzzy system, are presented to show the effectiveness of the proposed methodology

Continuous Stability TS Fuzzy Systems Novel Frame Controlled by a Discrete Approach and Based on SOS Methodology

Generally, the continuous and discrete TS fuzzy systems’ control is studied independently. Unlike the discrete systems, stability results for the continuous systems suffer from conservatism because it is still quite difficult to apply non-quadratic Lyapunov functions, something which is much easier for the discrete systems. In this paper and in order to obtain new results for the continuous case, we proposed to connect the continuous with the discrete cases and then check the stability of the continuous TS fuzzy systems by means of the discrete design approach. To this end, a novel frame was proposed using the sum of square approach (SOS) to check the stability of the continuous Takagi Sugeno (TS) fuzzy models based on the discrete controller. Indeed, the control of the continuous TS fuzzy models is ensured by the discrete gains obtained from the Euler discrete form and based on the non-quadratic Lyapunov function. The simulation examples applied for various models, by modifying the order of the Euler discrete fuzzy system, are presented to show the effectiveness of the proposed methodology

Numerical Study of Mechanical Stirring in Case of Yield Stress Fluid with Circular Anchor Impeller

In this work the characterization of hydrodynamic fields of incompressible yield stress fluid with regularization model of Bercovier and Engelman in a cylindrical vessel not chicaned equipped with circular anchor stirrer was undertaken by means of numerical simulation using computational fluid dynamics. Simulations flow of a Bingham fluid agitated by straights blades anchor was used to validate the rheological model implemented of the fluid treated. The flow structures, and especially the effect of inertia, the plasticity and the yield stress, are discussed. We have analyzed also the influence of rheological parameters on the hydrodynamic flow behaviours, such as the velocity components and the global characteristic like power consumption

Histological changes in the uterine of female rats after a comparative treatment with Trigonella foenum-graecum seeds and combined oral contraceptive pills

Introduction: This study evaluates the histological changes of uterine tissue in the female Sprague Dawley rats after administration of Trigonella foenum-graecum (fenugreek) seeds in comparison to combined oral contraceptive pills (COCPs). Methods: Twenty four female Sprague Dawley strain rats of 8 weeks old were divided into A, B, and C groups. Group A was the control and B was administrated with 0.05 mg/kg body weight of COCPs for 15 days. Group C was treated with 750 mg/kg body weight of fenugreek seed aqueous (FSA) extract for 15 days. The uterine tissues were isolated and studied histologically. Results: The uterine weight in the FSA extract treated group was normal, while in the COCPs treated group it was insignificantly increased. The endometrial thickness and endometrial gland density were normal in the FSA extract treated group, while in the COCPs treated group it was atrophied. Decidual-like cells were observed in the COCPs treated group only. Conclusions: Endometrial atrophy and decidual-like cells were noted after COCPs treatment while in the FSA extract and control groups they were absent. The findings suggest that fenugreek seeds could be used as an alternative natural and safe contraceptive product