Floral odors and the interaction between pollinating Ceratopogonid midges and Cacao

Most plant species depend upon insect pollination services, including many cash and subsistence crops. Plants compete to attract those insects using visual cues and floral odor which pollinators associate with a reward. The cacao tree, Theobroma cacao, has a highly specialized floral morphology permitting pollination primarily by Ceratopogonid midges. However, these insects do not depend upon cacao flowers for their life cycle, and can use other sugar sources. To understand how floral cues mediate pollination in cacao we developed a method for rearing Ceratopogonidae through several complete lifecycles to provide material for bioassays. We carried out collection and analysis of cacao floral volatiles, and identified a bouquet made up exclusively of saturated and unsaturated, straight-chain hydrocarbons, which is unusual among floral odors. The most abundant components were tridecane, pentadecane, (Z)-7-pentadecene and (Z)-8-heptadecene with a heptadecadiene and heptadecatriene as minor components. We presented adult midges, Forcipomyia sp. (subgen. Forcipomyia), Culicoides paraensis and Dasyhelea borgmeieri, with natural and synthetic cacao flower odors in choice assays. Midges showed weak attraction to the complete natural floral odor in the assay, with no significant evidence of interspecific differences. This suggests that cacao floral volatiles play a role in pollinator behavior. Midges were not attracted to a synthetic blend of the above four major components of cacao flower odor, indicating that a more complete blend is required for attraction. Our findings indicate that cacao pollination is likely facilitated by the volatile blend released by flowers, and that the system involves a generalized odor response common to different species of Ceratopogonidae

Numerical Investigation of Jet Effects on the Dornier 328 EC Wind Tunnel Model

A model of the Dornier 328 JET transport aircraft with two mounted Turbine Powered Simulators (TPS) has been tested in the Low Speed wind tunnel (DNW-NWB) at the DLR in Braunschweig (Germany). During the tests it was observed that with increasing thrust the lift coefficient decreased. It was assumed that the increasing engine jet velocity decreases the pressure below the wing in the vicinity of the pylon and therefore the lift of the whole airplane would be reduced. In order to examine this strong influence of the engine jet as cause for the reduction of lift, numerical flow-simulations with an Euler-solver for unstructured tetrahedral grids were performed. The result of these numerical investigations is, that this effect could not be confirmed, the lift stayed nearly constant. Additionally the iso-Mach number distributions on the pylon and the rear of the nacelle for different power settings do not vary significantly

A new crystallization process in polyproplylene highly filled with calcium carbonate

The influence of high amounts of calcium carbonate filler on the crystallization behavior of PP is investigated by DSC and fast scanning DSC measurements. The non-isothermal crystallization process at industrially relevant cooling rates of about 100 K/s is significantly influenced by the calcium carbonate filler. Isothermal crystallization measurements indicate a new crystallization process in the temperature range between 45 °C and 80 °C caused by the filler content. To find an explanation for the origin of this process we have analyzed the interaction between polymer and filler, the crystalline structure and the crystallization kinetics. From the experimental results we conclude that the newly observed crystallization process is governed by an additional nucleation process for the growth of a-phase crystals

A new crystallization process in polyproplylene highly filled with calcium carbonate

The influence of high amounts of calcium carbonate filler on the crystallization behavior of PP is investigated by DSC and fast scanning DSC measurements. The non-isothermal crystallization process at industrially relevant cooling rates of about 100 K/s is significantly influenced by the calcium carbonate filler. Isothermal crystallization measurements indicate a new crystallization process in the temperature range between 45 °C and 80 °C caused by the filler content. To find an explanation for the origin of this process we have analyzed the interaction between polymer and filler, the crystalline structure and the crystallization kinetics. From the experimental results we conclude that the newly observed crystallization process is governed by an additional nucleation process for the growth of a-phase crystals