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Experimental Advances (experimental + advance)
Selected AbstractsCarbon Nanotubes and Nanofluidic TransportADVANCED MATERIALS, Issue 35 2009Jason Knowles Holt Abstract Recent strides have been made in both the modeling and measurement of fluid flow on the nanoscale. Carbon nanotubes, with their atomic dimensions and atomic smoothness, are ideal materials for studying such flows. This Progress Report describes recent modeling and experimental advances concerning fluid transport in carbon nanotubes. The varied flow characteristics predicted by molecular dynamics are described, as are the roles of defects and chirality on transport. Analytical models are increasingly being used to describe nanofluidic transport by relaxing many of the assumptions commonly used to describe bulk water. Recent experimental studies examine the size dependence of flow enhancements through carbon nanotubes and use varied spectroscopies to probe water structure and dynamics in these systems. Carbon nanotubes are finding increasing applications in biology, from protein filters to platforms for cell interrogation. [source] Linear and non-linear optical experiments based on macroporous silicon photonic crystalsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2007Ralf B. Wehrspohn Abstract Macroporous silicon is a model system for 2D silicon photonic crystals. In this review, we describe our recent theoretical and experimental advances in the macroporous silicon technology as well as in novel near-field optical experiments concerning modified light emission from photonic crystal cavities and waveguides. We also review our recent work on tuning silicon photonic crystals by free-carriers or non-linear effects and compare the two tuning mechanisms. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Superparasitism in gregarious hymenopteran parasitoids: ecological, behavioural and physiological perspectivesPHYSIOLOGICAL ENTOMOLOGY, Issue 3 2007SILVIA DORN Abstract Superparasitism in gregarious wasps occurs with the deposition of a clutch of eggs by a female into a host already parasitized by itself or a conspecific female. This review synthesizes and interprets the available results in the literature reported from field studies, and from behavioural and physiological investigations. To study superparasitism at the ecosystem level, methodological issues have to be solved to determine threshold values beyond which multiple offspring can be indisputably classified as originating from superparasitism. This life strategy is then discussed from the parasitoid's perspective, considering time and egg limitation, host discrimination, clutch size, offspring body size and sex ratio, as well as development time and survival rate of offspring, with special emphasis on physiological facilitation and constraints. Then, superparasitism in gregarious species is evaluated from the host's angle, addressing host survivorship and development, host food consumption and growth. Although superparasitism may be beneficial for either the first or the superparasitizing female, depending on the system, it is detrimental for both of them under conditions of extreme superparasitism. Recent methodological and experimental advances encourage further studies on the adaptive host choice under field and laboratory conditions, as well as on mechanisms underlying success of the first or the superparasitizing female and their progeny. [source] Role of the interphase in the flow stability of reactive coextruded multilayer polymersPOLYMER ENGINEERING & SCIENCE, Issue 4 2009Khalid Lamnawar Coextrusion technologies are commonly used to produce multilayered composite sheets or films for a large range of applications from food packaging to optics. The contrast of rheological properties between layers can lead to interfacial instabilities. Important theoretical and experimental advances regarding theses defects have, during the last decades, been made using a mechanical and numerical approach. This study deals with the influence of the physicochemical affinity between the neighboring layers on interfacial instabilities for functionalized incompatible polymers. It was experimentally confirmed, in this case, that weak disturbance can be predicted by considering an interface of nonzero thickness (corresponding to an interdiffusion/reaction zone interphase) instead of a purely geometrical interface between the two reactive layers. According to the rheological investigations, an experimental strategy was here formulated to investigate the parameters that controlled the stability of the reactive multilayer flows. The role of the viscosity ratio, elasticity ratio, and layer ratio of the stability of the interface was also investigated coupling to the reaction rate/compatibilization phenomenon. Hence, based on this analysis, guidelines for a stable coextrusion of reactive functionalized polymers can be provided coupling the classical parameters and the physicochemical affinity at the polymer/polymer interface. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source] | ||||||||||