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Aims: The study was conducted to (i) determine the effectiveness of the local-based food security intervention in improving the knowledge and practice of mothers in infant and young child feeding (IYCF) practices, and (ii) assess the effectiveness of the intervention in improving the nutritional status of children under five years in two communes in Lao Cai province. Methods: The open community intervention was conducted from 2014 to 2016 on all children under five years old and their primary caregivers in Thao Chu Phin and Ban Pho commune, Lao Cai province. Care Group consisted of 10-12 mothers/primary caregivers, and Village Kitchen consisted of a group of women in the village, were established and met weekly to enhance rice powder production and peer communication activities in the communes. All 150 and 194 pairs of child-primary caregiver at baseline and the end of the intervention, respectively were assessed for children’s weight and height, and primary caregivers’ knowledge, attitude, and practices on IYCF. Results: The prevalence of stunting significantly reduced at the conclusion of the intervention, from 59.3 to 43.5% in Ban Pho commune (p

The rollover phenomenon is quite familiar with trucks and often has severe consequences worldwide. This article focuses on developing a new control structure for the active antiroll bar system using the robust control method. The main objective is to improve the vehicle’s roll stability by using additional suspension roll angle sensors. First, a truck model equipped with an active antiroll bar system is introduced. Then, the basic robust controller structure diagram is described in detail. Based on this basic robust controller, the authors develop a new robust controller considering the suspension roll angle sensors. Finally, the response of a truck using an active antiroll bar system with two robust (H∞) controllers and a passive antiroll bar system is compared and evaluated in the time domain and in the frequency domain. The results showed that the use of two sensors of the suspension roll angle sensors increased the efficiency by about 20% compared to the basic robust controller. This has proven the effectiveness of a new approach in improving the roll stability of trucks.

Rollover accidents of heavy vehicles often cause serious consequences both in terms of vehicle and environmental damage as well the loss or injury of drivers, passengers and ordinary civilians. Currently, the active anti-roll bar system is considered as the most effective solution in enhancing vehicle roll stability. In this paper, we firstly investigated the role of a flexible frame of a single unit heavy vehicle in the rollover process. This approach is an important step forward in the research of the active anti-roll bar system. Then, the LQR control method is applied in designing controllers for the active anti-roll bar control system with this frame model. The active torque of the anti-roll bar system is considered as the control signal. The simulation results in the frequency and time domains with a double lane change maneuver show that the vehicle’s roll stability is improved by over 30 % compared to a vehicle using a passive anti-roll bar system.

The complexity of railway vehicle structures has been part of an evolutionary process for almost two hundred years. Challenges such as increased weight, increased maintenance, higher costs and energy consumption have become common. The vision for future railway vehicles is to reduce complexity, hence enable simpler structures and reduce maintenance and cost, and of course various research challenges arise from this. In fact, a number of papers in the railway engineering literature have presented practical ways to control steering of railway vehicles to improve performance. The model of the railway wheelset is highly nonlinear, mainly due to the nature of the wheelset structure and the related wheel-rail contact forces involved during operation. In this paper, the simplest design in terms of retrofitting, the actuated solid-axle wheelset is considered, we investigate actively controlled wheelsets from a Linear Parameter Varying (LPV) control aspect. We use the grid-based LPV approach to synthesize the H∞ / LPV controller, which is self-scheduled by the forward velocity, as well as the longitudinal and lateral creep coefficients. The aim of the controller is to reduce the lateral displacement and yaw angle of the wheelset. Simulation results show that the proposed controller ensures the achievement of the above targets in the considered frequency domain up to 100 rad/s.

The Electronic Servo-Valve Hydraulic (ESVH) actuator is commonly used in the industrial sector and engineering practice. This paper investigates the robustness of the $$\mathcal{H}_\infty$$ /LPV active anti-roll bar system when the presence of an oil leakage inside the electronic servo-valve is taken into account. We propose a fully integrated model, including four ESVH actuators in a single unit heavy vehicle. Then, an $$\mathcal{H}_\infty$$ /LPV controller is synthesized in order to satisfy simultaneously the two main objectives of enhancing roll stability and the saturation of the actuators. Survey results indicate that the oil leakage has a positive effect in protecting the active anti-roll bar system if the controller stops working and it is indispensable for this type system. At each design point of the LPV system, the μ-tool method is used to test the robustness analysis in the frequency domain. It is shown that the active anti-roll bar system is always robust with the maximum uncertain level of the total flow pressure coefficient of 41%, when the forward velocity is considered to be over 130 km/h.

The active braking control system is an active safety system designed to prevent accidents and to stabilize dynamic manoeuvers of a vehicle by generating an artificial yaw moment using differential braking forces. In this paper, the yaw-roll model of a single unit heavy vehicle is used for studying the active braking system by using the longitudinal braking force at each wheel. The grid-based LPV approach is used to synthesize the H∞/LPV controller by considering the parameter dependant weighting function for the lateral acceleration. The braking monitor designs are proposed to allow the active braking system to react when the normalized load transfer at the rear axle reaches the criteria of rollover ±1. The simulation results indicate that the active braking system satisfies the adaptation of vehicle rollover in an emergency situation, with low braking forces and improved handling performance of the vehicle.

This paper presents an LPV damping force observer of Electro Rheological (ER) dampers for a real automotive suspension system, taking the dynamic characteristic of damper into account. First, an extended nonlinear quarter-car model is considered, where the time constant representing the damper dynamics is varying according to the control level. This is rewritten as an LPV model which is used to design an LPV observer. The objective of the LPV observer is to minimize the effects of bounded unknown input disturbances (unknown road profile and measurement noises) on the state estimation errors through an H∞ criterion, while the damper nonlinearity is bounded using a Lipschitz condition. Two low-cost accelerometers (the sprung mass and the unsprung mass accelerations) are used as inputs for the proposed methodology only. To experimentally assess the proposed approach, the observer is implemented on the 1/5-scaled real vehicle-INOVE testbench of GIPSA-lab. Experiments shows the ability of the observer to estimate the damper force in real-time, face to unknown inputs disturbance and sensor noises.

The active anti-roll bar system has been proven to be one of the most effective solutions to improve roll stability of heavy vehicles. In a previous work, the authors proposed an H∞ controller for this system. The Genetic Algorithms method was used to handle the vehicle roll stability and the energy consumption of the actuators via the Pareto optimality. This paper aims to assess the overall effectiveness of the proposed controller with nonlinear heavy vehicle models, which are already set up in the TruckSim® software. The controller is then evaluated in hard conditions to show the high performance and robust with the nonlinearity effects, such as the load distribution between the two axles, the side wind gusts and the abrupt steering. To conduct testing of the H∞ active anti-roll bar control system, we propose a co-simulation structure between TruckSim® and Simulink®: the nonlinear vehicle model is determined from TruckSim®, based on using the block S-function of Simulink. Meanwhile, the controller and the actuators are built directly in the Matlab/Simulink ® environment. The validation results are made through two different types of heavy vehicles: a tour bus and a truck, using a selection of different velocities and scenarios. The results show that by using the H∞ active anti-roll bar control system, in comparison to the passive anti roll bar system, roll stability is improved to minimise the risk of vehicle rollover.

Silica/Polypyrrole nanocomposites (SiO2/PPy) incorporating oxalate as counter anion (SiO2/PPyOx) were chemically polymerized in the solution with the presence of pyrrole, silica, and sodium oxalate. Nanocomposites SiO2/PPyOx at different concentrations of oxalate anion were characterized with FTIR, XRD, EDX, TGA, and TEM. The corrosion protective properties for carbon steel of nanocomposites in epoxy coating were studied by electrochemical techniques including electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP). FTIR results of nanocomposites show a slightly red-shift in terms of wavelength compared with the case of PPy and SiO2 spectra. It may be due to a better conjugation and interactions between PPy and SiO2 in nanocomposite structure. TEM image indicated that nanocomposites have spherical morphologies with diameters between 100 and 150 nm. The EIS results showed that |Z| modulus values of epoxy coatings containing SiO2/PPyOx composites reached about 109.7 Ω.cm2, always higher than that of epoxy coating. These results are also confirmed by OCP results. It proves that the presence of oxalate anion can enhance the resistance against corrosion and it has been shown that the content of counter anion strongly affects the anticorrosion ability.

DOI : 10.1016/j.ifacol.2017.08.2071; International audience; In the active anti-roll bar control on heavy vehicles, roll stability and energy consumption of actuators are two essential but conflicting performance objectives. In a previous work, the authors proposed an integrated model, including four electronic servo-valve hydraulic actuators in a linear yaw-roll model on a single unit heavy vehicle. This paper aims to design an H ∞ active anti-roll bar control and solves a Multi-Criteria Optimization (MCO) problem by using Genetic Algorithms (GAs) to select the weighting functions for the H ∞ synthesis. Thanks to GAs, the roll stability and the energy consumption are handled using a single high level parameter and illustrated via the Pareto optimality. Simulation results in frequency and time domains emphasize the efficiency of the use of the GAs method for a MCO problem in H ∞ active anti-roll bar control on heavy vehicles.

International audience; Rollover of heavy vehicle is an important road safety problem worldwide. Although rollovers are relatively rare events, they are usually deadly accidents when they occur. The roll stability loss is the main cause of rollover accidents in which heavy vehicles are involved. In order to improve the roll stability, most of modern heavy vehicles are equipped with passive anti-roll bars to reduce roll motion during cornering or riding on uneven roads. However these may be not sufficient to overcome critical situations. This paper introduces the active anti-roll bars made of four electronic servo-valve hydraulic actuators, which are modelled and integrated in a yaw-roll model of a single unit heavy vehicle. The control signal is the current entering the electronic servo-valve and the output is the force generated by the hydraulic actuator. The active control design is achieved solving a linear optimal control problem based on the Linear Quadratic Regulator (LQR) approach. A comparison of several LQR controllers is provided to allow for tackling the considered multi-objective problems. Simulation results in frequency and time domains show that the use of two active anti-roll bars (front and rear axles) drastically improves the roll stability of the single unit heavy vehicle compared with the passive anti-roll bar.

Conventional wind tunnel tests for modelling the self-excited responses of slender structures under wind actions considered the wind normal to a structural axis, allowing the testing model vibrating in a direction normal to the wind. This paper discusses the issue of how to model the self-excited responses of slender structures under wind actions in wind tunnel, where the structures can vibrate in both directions normal on inclined to the wind through a series of wind tunnel tests on a square cylinder. The self-excited responses, including vortex-induced vibration and galloping, are then estimated. This study provides a further insight of the aeroelastic phenomena of square-section prisms.

Today, articulated vehicles are widely used in the world because they benefit the society. However, accidents related to articulated vehicles tend to be fatal, one of the main reasons is the instability of articulated vehicles. This paper is concerned with the dynamic modeling of tractor–semi trailer vehicles. A simplified linear model is proposed, which includes the roll and yaw motions, based on the assumption that the longitudinal velocity is constant. The simulation results in a cornering and a double lane change manoeuver show that the stability of tractor-semi trailer depends on the stiffness and damping coefficients and the forward velocity. Therefore, in order to improve the vehicle roll stability, three types of active anti-roll bar system for the tractor-semi trailer are proposed: the first and second systems are equipped only for tractor and trailer respectively, while the last one can be used for both kinds of vehicles.