Evolution of vacancy pores in bounded particles

In the present work, the behavior of vacancy pore inside of spherical particle is investigated. On the assumption of quasistationarity of diffusion fluxes, the nonlinear equation set was obtained analytically, that describes completely pore behavior inside of spherical particle. Limiting cases of small and large pores are considered. The comparison of numerical results with asymptotic behavior of considered limiting cases of small and large pores is discussed.Comment: 25 pages, 10 figure

Effect of Vinyl and Silicon Monomers on Mechanical and Degradation Properties of Bio-Degradable Jute-Biopol® Composite

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Composites of jute fabrics (Hessian cloth) and Biopol® were prepared by compression molding process. Three types of Biopol® (3-hydroxbutyrate-co-3-hydroxyvalarate) such as D300G, D400G and D600G, depending on the concentration of 3-hydroxyvalarate (3HV) in 3-hydroxbutyrate (3HB) were taken for this purpose. Mechanical properties such as tensile strength (TS), bending strength (BS), elongation at break (Eb) and impact strength (IS) of the jute-Biopol® composites were studied. It was found that the composite with D400G produced higher mechanical properties in comparison to the other two types of Biopol®. To increase mechanical properties as well as interfacial adhesion between fiber and matrix, 2-ethyl hydroxy acrylate (EHA), vinyl tri-methoxy silane (VMS) and 3-methacryloxypropyl tri-methoxy silane (MPS) were taken as coupling agents. Enhanced mechanical properties of the composites were obtained by using these coupling agents. Biopol® D400G composites showed the highest mechanical properties. Among the coupling agents EHA depicts the highest increase of mechanical properties such as tensile strength (80%), bending strength (81%), elongation at break (33%) and impact strength (130%) compared pure Biopol. SEM investigations demonstrate that the coupling agents improve the interfacial adhesion between fiber and matrix. The surface of the silanized jute was characterized by FTIR and found the deposition of silane on jute fiber was observed. Soil degradation test proved that the composite prepared with EHA treated jute exhibits better degradation properties in comparison to pure Biopol®

Detecting atmospheric neutrino oscillations in the ATLAS detector at CERN

We discuss the possibility to study oscillations of atmospheric neutrinos in the ATLAS experiment at CERN. Due to the large total detector mass, a significant number of events is expected, and during the shutdown phases of the LHC, reconstruction of these events will be possible with very good energy and angular resolutions, and with charge identification. We argue that 500 live days of neutrino running could be achieved, and that a total of ~160 contained \nu_\mu events and ~360 upward going muons could be collected during this time. Despite the low statistics, the excellent detector resolution will allow for an unambiguous confirmation of atmospheric neutrino oscillations and for measurements of the leading oscillation parameters. Though our detailed simulations show that the sensitivity of ATLAS is worse than that of dedicated neutrino experiments, we demonstrate that more sophisticated detectors, e.g. at the ILC, could be highly competitive with upcoming superbeam experiments, and might even give indications for the mass hierarchy and for the value of theta-13.Comment: 8 pages, 4 figures, 2 tables, RevTeX 4; modified treatment of upward going muons, results unchanged; matches published versio

Phenotypic plasticity from a predator perspective: empirical and theoretical investigations

Phenotypic plasticity is common in predator-prey interactions. Prey use inducible defenses to increase their chances of survival in periods of high predation risk. Predators, in turn, display inducible offenses (trophic polyphenisms) and adjust their phenotypes to the prevailing type of prey. In the past, inducible defenses have received considerably more attention than inducible offenses. Here, I point out three areas where taking a predator perspective can increase our understanding of phenotypic plasticity in predator-prey systems. In Part 1, I describe an inducible offense in the predatory ciliate Lembadion bullinum: Mean cell size in a genetically uniform Lembadion population increases with the size of the dominant prey species. This size polyphenism can be explained as the result of a trade-off: Large Lembadion are superior in feeding on large prey, whereas small Lembadion achieve higher division rates when small prey is available. Consequently, inducible predator offenses may evolve as adaptations to environments where important prey characteristics vary over space or time. In Part 2, I investigate the interplay of Lembadion's inducible offense with an inducible prey defense. Lembadion releases a kairomone (i.e. an infochemical) that induces defenses in several prey species. For example, in the herbivorous ciliate Euplotes octocarinatus, it triggers the production of protective lateral "wings". I show that Lembadion can reduce the effect of this defense by activating its inducible offense. This is one of the first known examples of reciprocal phenotypic plasticity in a predator-prey system. While the counter-reaction of Lembadion decreases the fitness of the prey, it could not be shown to significantly increase the fitness of Lembadion itself. Nevertheless, I discuss the hypothesis that phenotypic plasticity in both species is a result of (diffuse) coevolution. In Part 3, I further pursue the idea of coevolution and develop a mathematical model of a coevolving predator-prey pair which displays reciprocal phenotypic plasticity. In this model, the inducible offense is a truly effective counter-adaptation to the prey's defense. The model yields three main conclusions: First, the inducible prey defense can stabilize predator-prey population dynamics. The effect of the inducible counter-offense is less clear and depends on the relative magnitude of its costs and benefits. Second, the maintenance of phenotypic plasticity requires that both the defense and the offense are sufficiently strong. Third, preliminary results suggest that an inducible offense is favored over a constitutive (permanently expressed) one if and only if the model populations perform predator-prey cycles. This leads to the hypothesis that phenotypic plasticity may evolve as an adaptation to temporal heterogeneity created by the internal dynamics of predator-prey systemsZusammenfassung 3 Abstract 5 General Introduction: A predator perspective on phenotypic plasticity 7 Part 1. Trophic size polyphenism in Lembadion bullinum: costs and benefits of an inducible offense 9 1.1 Introduction 9 1.2 Material and methods 11 1.3 Results 16 1.4 Discussion 24 Part 2. Reciprocal phenotypic plasticity in a predator prey system: inducible offenses against inducible defenses? 30 2.1 Introduction 30 2.2 Material and methods 31 2.3 Results 36 2.4 Discussion 39 Part 3. Modeling a coevolving predator-prey system with reciprocal phenotypic plasticity 44 3.1 Introduction 44 3.2 The model 47 3.3 Results 61 3.4 Discussion 127 Conclusions 133 Acknowledgements 134 Danksagungen 135 Literature cited 136 Curriculum vitae 147 Lebenslauf 14

Profile Monitor SEM's for the NuMI Beam at FNAL

The Neutrinos at the Main Injector (NuMI) project will extract 120 GeV protons from the FNAL Main Injector in 8.56usec spills of 4E13 protons every 1.9 sec. We have designed secondary emission monitor (SEM) detectors to measure beam profile and halo along the proton beam transport line. The SEM?s are Ti foils 5um in thickness segmented in either 1?mm or 0.5?mm pitch strips, resulting in beam loss ~5E-6. We discuss aspects of the mechanical design, calculations of expected beam heating, and results of a beam test at the 8 GeV transport line to MiniBoone at FNAL.Comment: to appear in proceedings of 11th Beam Instrumentation Workshop, Oak Ridge, T