Compared to conventional powertrains, hybrid electric vehicles exploit energy production and energy storage systems to achieve improved fuel economy. To maximize such improvement, advanced control strategies are needed for controlling in real-time the amount of energy to be produced and stored. This paper deals with the problem of hybrid energy storage system (HESS) for electric vehicle. The storage system consists of a fuel cell (FC), serving as the main power source, and a supercapacitor (SC), serving as an auxiliary power source. It also contains a power block for energy conversion consisting of a boost converter connected with the main source and a boost-buck converter connected with the auxiliary source. The converters share the same dc bus which is connected to the traction motor through an inverter. These power converters must be controlled in order to meet the following requirements: i) tight dc bus voltage regulation; ii) perfect tracking of SC current to its reference; iii) and asymptotic stability of the closed loop system. A nonlinear controller is developed, on the basis of the system nonlinear model, making use of Lyapunov stability design techniques. The latter accounts for the power converters large-signal dynamics as well as for the fuel-cell nonlinear characteristics. It is demonstrated using both a formal analysis and numerical simulations that the developed controller meets all desired objectives.

Chronic mastitis is a prolonged inflammatory breast disease, and little is known about its etiology. We identified 85 cases and 112 controls from 5 hospitals in Morocco and Egypt. Cases were women with chronic mastitis (including periductal, lobular, granulomatous, lymphocytic, and duct ectasia with mastitis). Controls had benign breast disease, including fibroadenoma, benign phyllodes, and adenosis. Both groups were identified from histopathologically diagnosed patients from 2008 to 2011, frequency-matched on age. Patient interviews elicited demographic, reproductive, breastfeeding, and clinical histories. Cases had higher parity than controls (OR = 1.75, 1.62–1.90) and more reported history of contraception use (OR = 2.73, 2.07–3.61). Cases were less likely to report wearing a bra (OR = 0.56, 0.47–0.67) and less often used both breasts for breastfeeding (OR = 4.40, 3.39–5.72). Chronic mastitis cases were significantly less likely to be employed outside home (OR = 0.71, 0.60–0.84) and more likely to report mice in their households (OR = 1.63, 1.36–1.97). This is the largest case-control study reported to date on risk factors for chronic mastitis. Our study highlights distinct reproductive risk factors for the disease. Future studies should further explore these factors and the possible immunological and susceptibility predisposing conditions.

This study deals with the problem of controlling hybrid storage systems in electric vehicles. The storage system includes a DC‐to‐DC switched power converter of boost type associated with a fuel‐cell generator and a buck boost converter connected to a supercapacitor. Both converters operate according to the PWM principle and the whole system model is nonlinear and subject to parameter uncertainties. The control objective is threefold: ensuring a tight dc bus voltage regulation despite the uncertainties on the fuel cell (FC) voltage–current characteristic and on the load converter; (2) guaranteeing a perfect tracking of supercapacitor (SC) current to its reference despite the SC capacitance uncertainty; ensuring asymptotic stability of the closed‐loop system. The control problem is dealt with using a nonlinear adaptive controller designed by the Lyapunov approach. It is formally shown that the proposed controller meets all its control objectives. This theoretical achievement is confirmed by several simulations.

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