polybrominated diphenyl ethers as flame retardants prevent the branching mechanism of free radicals in gas phase during the combustion. therefore, they are used in electric and electronical instruments. these supplies are entering the landfills after use. the existing flame retardants in these landfills enter the air, water and soil and pollute them. in this paper a mass-transfer model is devel...

The objectives of this study were to investigate Engineering students’ attitudes and problems in academic reading comprehension and to determine the contribution of academic reading attitude, breadth and depth of vocabulary knowledge to academic reading comprehension. The participants were 122 undergraduate students of Engineering at Iran University of Science and Technology. The Vocabulary Lev...

Because the constant extension ensemble of single chain molecule is not always equivalent with constant force ensemble, a model of double-stranded conformations, as in RNA molecules and βsheets in proteins, with fixed extension constraint is built in this paper. Based on polymer-graph theory and the self-avoiding walks, sequence dependence and excluded-volume interactions are explicitly taken i...

in the United Kingdom of those days. There was a time when Sir Robert Peel, the Prime Minister was told by a President of one of the then Royal Colleges: "No man who has an academic education ought to practise obstetrics." The same gentleman stated amidst applause in a subsequent meeting: "Obstetrics is no calling for a gentleman". The story in the book tells us how in 1946 in the same kingdom ...

Relatively extremal knots are the relative minima of the ropelength functional in the C1 topology. They are the relative maxima of the thickness (normal injectivity radius) functional on the set of curves of …xed length, and they include the ideal knots. We prove that a C1;1 relatively extremal knot in Rn either has constant maximal (generalized) curvature, or its thickness is equal to half of ...

We present a method to construct a large family of Lagrangian surfaces in complex Euclidean plane C by using Legendre curves in the 3-sphere and in the anti de Sitter 3-space or, equivalently, by using spherical and hyperbolic curves, respectively. Among this family, we characterize minimal, constant mean curvature, Hamiltonianminimal and Willmore surfaces in terms of simple properties of the c...

ACKNOWLEDGEMENTS I would like to thank my adviser Michael Zieve for teaching me to fish. I would like to thank Jeffrey Lagarias for helpful feedback in writing this thesis. I would like to thank my family (Peter, Susan, and Holly), my beautiful girlfriend Becky, and the community of Michigan graduate students for keeping me sane.