Interactive optimal design of truss structures

A CAD system based on combining structural optimization methods and graphical interaction is presented. The optimization methods implement the automated decisions and algorithms while the interaction provides the means to implement the designer's decisions. A new interactive optimization procedure for optimal truss design is proposed. The structural topology, geometry and member sizes are treated as design variables. Results show that the system provides a powerful tool to obtain a practical optimum design.     

Decomposition of trichloroethylene and tetrachloroethylene in drinking water by a combined radiation/ozone treatment

The decomposition of small amounts (100 ppb) of tri- or perchloroethylene in drinking water has been investigated. The combined action of γ-radiation and ozone results in a considerable synergistic effect. Furthermore, the presence of ozone eliminates completely the formation of nitrite occurring under γ-irradiation alone.     

Modern developments in wind engineering: part 2

This is the second in a series of review papers devoted to the state-of-the-art in wind engineering. The first paper, consisting of an introduction to the series and a discussion of engineering aspects of the wind environment, is published in this issue of Engineering Structures, pp233–241.     

Finding the global minimum: a fuzzy end elimination implementation

The ‘fuzzy end elimination theorem’ (FEE) is a mathematicallyproven theorem that identifies rotameric states in proteinswhich are incompatible with the global minimum energy conformation.While implementing the FEE we noticed two different aspectsthat directly affected the final results at convergence. First,the identification of a single dead-ending rotameric state cantrigger a ‘domino effect’ that initiates the identificationof additional rotameric states which become dead-ending. A recursivecheck for deadending rotameric states is therefore necessaryevery time a dead-ending rotameric state is identified. It isshown that, if the recursive check is omitted, it is possibleto miss the identification of some dead-ending rotameric statescausing a premature termination of the elimination process.Second, we examined the effects of removing dead-ending rotamericstates from further considerations at different moments of time.Two different methods of rotameric state removal were examinedfor an order dependence. In one case, each rotamer found tobe incompatible with the global minimum energy conformationwas removed immediately following its identification. In theother, dead-ending rotamers were marked for deletion but retainedduring the search, so that they influenced the evaluation ofother rotameric states. When the search was completed, all markedrotamers were removed simultaneously. In addition, to expandfurther the usefulness of the FEE, a novel method is presentedthat allows for further reduction in the remaining set of conformationsat the FEE convergence. In this method, called a tree-basedsearch, each dead-ending pair of rotamers which does not leadto the direct removal of either rotameric state is used to reducesignificantly the number of remaining conformations. In thefuture this method can also be expanded to triplet and quadrupletsets of rotameric states. We tested our implementation of theFEE by exhaustively searching ten protein segments and foundthat the FEE identified the global minimum every time. For eachsegment, the global minimum was exhaustively searched in twodifferent environments: (i) the segments were extracted fromthe protein and exhaustively searched in the absence of thesurrounding residues; (ii) the segments were exhaustively searchedin the presence of the remaining residues fixed at crystal structureconformations. We also evaluated the performance of the methodfor accurately predicting side chain conformations. We examinedthe influence of factors such as type and accuracy of backbonetemplate used, and the restrictions imposed by the choice ofpotential function, parameterization and rotamer database. Conclusionsare drawn on these results and future prospects are given     

Self-help groups: A referral resource for professional therapists.

Discusses the nature, structure, limitations, and potential of self-help organizations. The effective utilization of self-help organizations requires the referring therapist's awareness of the goals, methods, and services provided by the group and evaluation of the unique needs of potential group members. The value of self-help groups may depend on appropriate referral by psychotherapists. (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hyperfine and Structural Isotope Effects in Muonated Cyclohexadienyl and Cyclopentyl Radicals

Incorporation of muonium, the ultra-light isotope of hydrogen with a mass of only one-ninth the mass of H, leads to pronounced isotope effects in hyperfine coupling constants of radicals. They reflect the mass dependence of the internal dynamics. A detailed analysis is presented for the cyclohexadienyl and the cyclopentyl radicals. It is concluded that the isotope dependent bond length in an anharmonic potential accounts quantitatively for the observed effects in rigid species.