Sliding mode control algorithms with classical and modified discontinuous reaching laws for purely magnetic attitude control of small satellites are proposed and compared with each other in this work. They are designed by following the steps characteristic to the variable structure control method and the magnetic attitude control problem. The asymptotical stability of the control laws is proven...

The Environmental Protection Agency needs a mission statement. It needs this mission statement for a variety of reasons, not the least of which is to enhance the development and use of science pertinent to protecting the environment. Given the constraints of our nation's deeply legalistic approach to environmental problems, the amount of scientific information that has been developed and incorp...

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Dioxins (PCDDs) and furans (PCDFs) exposure has been linked to birth detects, child growth retardation, reduced levels of male reproductive hormones, altered ratios of male to female births, diabetes and cancer. These show that PCDDs and PCDFs give awful impact to man-kind. This paper will highlight on the concentration of the contaminants in fish and shellfish as well as the estimate intake of...

The environmental impact assessment process (EIA) for projects, programs, concepts and the financial assistance was approved officially for the first time in 1969 by the law on national environmental policy accepted in the USA. The mentioned process was developed through the legal directive of the Economic Commission for Europe (ECE) in 1985, by which the minimum requirements to the EIA were es...

PROBLEM Motor vehicle crashes kill more adolescents in the United States than any other cause, and often the teen is not wearing a seat belt. METHODS Using data from the 2011 Youth Risk Behavior Surveys from 38 states, we examined teens' self-reported seat belt use while riding as a passenger and identified individual characteristics and environmental factors associated with always wearing a ...