A Sequential Discontinuous Galerkin Method for the Coupling of Flow and Geomechanics

A decoupled and sequential numerical method is proposed and analyzed for solving the linear poroelasticity equations. Unlike other splitting approaches, this method is not iterative, which results in a speed-up of the computational time. The interior penalty discontinuous Galerkin method is employed for the spatial discretization and is combined with the backward Euler method for the time discretization. We provide a convergence analysis of the scheme along with numerical results that confirm the theoretical results.     

Pea and Broad Bean Pods as a Natural Source of Dietary Fiber: The Impact on Texture and Sensory Properties of Cake

Attention has focused on bakery products such as cake which is one of the most common bakery products consumed by people in the world. Legume by‐products, pea pods (PPs) (Pisum sativum L.) and broad bean pods (BBPs) (Vicia faba L.) mediterranean (Tunisian), has been studied for its high dietary fiber content (PP: 43.87 g/100 g; BBP: 53.01 g/100 g). Protein content was also a considerable component for both by‐products. We investigated the effect of substituted of 5%, 10%, 15%, 20%, 25%, and 30% of PP and BBP flours on the sensory and technological properties in cake. Cakes hardness increased whereas L^* and a^* color values decreased. The overall acceptability rate showed that a maximum of 15% of PP and BBP flours can be added to prepare acceptable quality cakes.     

Robust fault estimation and fault-tolerant tracking control for uncertain Takagi–Sugeno fuzzy systems: Application to single link manipulator

This article concerns the estimation and tracking control problems for Takagi–Sugeno systems with disturbances and norm bounded uncertainties in presence of sensor and actuator faults (SAF). First, we propose a robust fuzzy observer (RFO) design method to estimate both state and SAF for the considered class of the nonlinear systems. Then, this RFO-based fault tolerant tracking control is developed not only to compensate the SAF effects but also to ensure the state convergence to desired trajectories in spite of their presence. To reduce the conservatism of design conditions, observer and controller gains are calculated in a single step by solving a set of linear matrix inequality constraints. H_∞ criterion is used to attenuate disturbance effects and to reduce the tracking error. Finally, simulation results by considering two types of actuator fault and comparative study on a single link flexible joint manipulator are provided to underline the performances of the mentioned process.     

Photodegradation of sulcotrione in various aquatic environments and toxicity of its photoproducts for some marine micro-organisms

Photochemical behaviour of sulcotrione, a triketone herbicide, was studied in a variety of aqueous solutions including natural waters (sea and river) under laboratory conditions. Photodegradation experiments were carried out under two irradiation systems (UV-B and simulated solar radiation) in order to evaluate kinetics of active ingredient. The degradation kinetics, more rapid under UV-B radiation than solar simulator, followed a first-order reaction (photolysis half-lives ranged between 3 and 50 h) and appeared strongly dependent on water origin, pH value and molecular structure of the herbicide. Dissolved organic matter showed a retarding effect while low concentrations of nitrate ions had no effect on photolysis rate. Identification of photoproducts indicated that hydrolysis, a pH-dependent process (no degradation at pH >6 but at pH=3, k=0.0344 h(-1)), could be photoassisted. These results were compared to those of mesotrione, another triketone herbicide, which appeared more stable under UV-B irradiation. Toxicological studies on two marine heterotrophic bacteria and one cyanobacterium showed absence of effects up to 100 microgL(-1) for both sulcotrione and its photoproducts.     

Exponential Stability Criteria for Positive Systems with Time-Varying Delay: A Delay Decomposition Technique

This paper is concerned with exponential stability analysis for linear continuous positive systems with bounded time-varying delay. Our approach is based on Lyapunov–Krasovskii functional with delay decomposition. The main idea is to divide uniformly the discrete delay interval into multiple segments and then to choose proper functionals with different weighted matrices corresponding to different segments. The synthesis of our delay-dependent sufficient stability criteria is formulated in terms of linear matrix inequalities. The proposed results are shown to be less conservative compared to other results from the literature. Some illustrative examples are given to show the effectiveness of the obtained results.     

Numerical investigations of the heating distribution effect on the boiling flow in bubble pumps

Numerical simulations of the heating repartition effect on the boiling flow in vertical tube are performed using the commercial CFD (Computational Fluid Dynamics) package FLUENT. The Eulerian multiphase flow framework model was applied to describe the phase interactions. User-Defined Functions (UDFs) are provided to compute the wall heat transfer and the inter-phase heat and mass transfer. Two different configurations of the bubble pump are considered: Total and partial heating of the pump tube.     

Robust $$\alpha $$-Stabilization of Uncertain Positive Takagi–Sugeno Systems with Time-Delay via Memory State-Feedback

This paper is concerned with the design of robust state-feedback controllers for uncertain positive Takagi–Sugeno systems with time-delay. The \(\alpha \)-stabilization by static state-feedback controllers with memory is investigated, taking into account the positivity and the interval uncertainties of the delayed closed-loop system into account. For this, new sufficient \(\alpha \)-stabilization conditions are established in terms of LMIs. An example illustrates of the proposed approach.     

Stability and Stabilization of Polynomial Fuzzy Systems with Time Delay: New Approach

This paper focuses on the stability and stabilization of polynomial fuzzy systems with time delay. This study is based on a polynomial Lyapunov–Krasovskii functional, and delay-dependent results are described in terms of bilinear sum of squares (SOS) conditions. Two techniques are presented, in this paper, to solve the problem of non-convexity of SOS stability and stabilization conditions for polynomial fuzzy systems with time delay. The first technique presents the SOS stability conditions for a specific class of polynomial fuzzy systems with time delay. Delay-dependent conditions are derived throughout a predefined set of indices. This technique improves delay-independent results existing in the literature. The second method transforms the design problem on an optimization problem subject to SOS constraints. The proposed SOS approach is more innovative and effective than the existing linear matrix inequality in terms of conservatism reduction. The new convex conditions for polynomial fuzzy systems with time delay are shown in terms of SOS which can be solved via SOSTOOLS software. Numerical examples are given to show the effectiveness of the proposed methods.     

Recent seismicity of Central High Atlas and Ouarzazate basin (Morocco)

The paper describes the tectonic evolution of the Central High Atlas and the Ouarzazate basin in Morocco, noting that many of the tectonic phenomena follow the previous structural lines. Although the area is one of relatively low seismicity, its location in an intra plate part of the African Plate and its high morphology, the effects of an earthquake could be considerable. This study combines seismic records from 1900 to 2007 with the integration of existing tectonic and structural information to better define the seismogenic zones. A newly identified cluster of epicenters in a NNW-SSE linear zone may be related to the Imilchil fault, where the earthquakes with magnitudes of 4–5 at depths of 5–20 km have been identified. Recent work in the Ouarzazate basin indicated that the Amekchoud fault ramp could generate seismic events with magnitudes as large as 6.4 Mw.