Evaluating Pore Space in Macroporous Ceramics with Water‐Based Porosimetry

We show that water‐based porosimetry (WBP), a facile, simple, and nondestructive porosimetry technique, accurately evaluates both the pore size distribution and throat size distribution of sacrificially templated macroporous alumina. The pore size distribution and throat size distribution derived from the WBP evaluation in uptake (imbibition) and release (drainage) mode, respectively, were corroborated by mercury porosimetry and X‐ray micro‐computed tomography (μ‐CT). In contrast with mercury porosimetry, the WBP also provided information on the presence of “dead‐end pores” in the macroporous alumina.     

An Optimizing Compiler for Automatic Shader Bounding

Programmable shading provides artistic control over materials and geometry, but the black box nature of shaders makes some rendering optimizations difficult to apply. In many cases, it is desirable to compute bounds of shaders in order to speed up rendering. A bounding shader can be automatically derived from the original shader by a compiler using interval analysis, but creating optimized interval arithmetic code is non‐trivial. A key insight in this paper is that shaders contain metadata that can be automatically extracted by the compiler using data flow analysis. We present a number of domain‐specific optimizations that make the generated code faster, while computing the same bounds as before. This enables a wider use and opens up possibilities for more efficient rendering. Our results show that on average 42–44% of the shader instructions can be eliminated for a common use case: single‐sided bounding shaders used in lightcuts and importance sampling.     

Patterns of Phytochemical Variation in Mimulus guttatus (Yellow Monkeyflower)

The search for general patterns in the production and allocation of plant defense traits will be facilitated by characterizing multivariate suites of defense, as well as by studying additional plant taxa, particularly those with available genomic resources. Here, we investigated patterns of genetic variation in phytochemical defenses (phenylpropanoid glycosides, PPGs) in Mimulus guttatus (yellow monkeyflower). We grew plants derived from several natural populations, consisting of multiple full-sibling families within each population, in a common greenhouse environment. We found substantial variation in the constitutive multivariate PPG phenotype and in constitutive levels of individual phytochemicals within plants (among leaves of different ages), within populations (among full-sibling families), and among populations. Populations consisting of annual plants generally, but not always, had lower concentrations of phytochemicals than did populations of perennial plants. Populations differed in their plastic response to artificial herbivory, both in the overall multivariate PPG phenotype and in the individual phytochemicals. The relationship between phytochemistry and another defense trait, trichomes, differed among populations. Finally, we demonstrated that one of the PPGs, verbascoside, acts as a feeding stimulant rather than a feeding deterrent for a specialist herbivore of M. guttatus, the buckeye caterpillar (Junonia coenia Nymphalidae). Given its available genetic resources, numerous, easily accessible natural populations, and patterns of genetic variation highlighted in this research, M. guttatus provides an ideal model system in which to test ecological and evolutionary theories of plant-herbivore interactions.     

Shear effect in beta‐phase induction of polypropylene in a single screw extruder

In this work, we investigated the effect of four different configurations at the exit of a single‐screw extruder on the induction of beta phase in PP for four different rotational speeds. The configuration of a breaker plate with 120 orifices of 1‐mm diameter and 7‐mm length each, give the highest content of beta‐phase (56.92%), for a screw rotational speed of 20 rpm. It was due to the shear caused separation of the melt when it passes through the orifices of the breaker plate. The breaker plate of configuration 4 (breaker plate with the greatest number of orifices) provided the largest number of contacts between the melt and the orifice walls resulting in chain alignment. The results show that the beta‐phase can be induced in the polymer without any further additives, especially without any nucleating agents, but rather by using a special breaker plate configuration at the exit of the single‐screw extruder. The skin‐core structure of the polymer was only developed with one type of extruder configuration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2932–2937, 2013     

Kombinierte Licht‐ und Radiowellenemission während des Bruches von Partikeln

The relationship between the light and radio impulses that appear during the stressing layers of glass particles was investigated. Particles were stressed between two metallic plates under applied high voltage. The emission of light appears during the development of the first cracks within the particle. The radio wave impulses were caused by electrical breakdown of a fragment layer. It appears after the light impulse. The delay between light and radio impulse of about a few micro seconds represents the characteristic time of size reduction.     

Synthesis and Biological Activity of 10‐Aza‐narciclasine

The first active aza analogue of narciclasine was synthesized from a pentasubstituted derivative of nicotinic acid. The key features of the synthesis include a halogen dance of bromopyridine and an intramolecular Heck reaction with a conduramine derived chemoenzymatically from bromobenzene. 10‐Aza‐narciclasine was found to have reasonable activity against several cancer cell lines.

     

Characterization of cross‐linking depth for thin polymeric films using atomic force microscopy

Thin polymeric films made with various elastomers, like polyisoprene, and elastomer composites were prepared for characterization of cross‐linking depth in this study. Various cross‐linking methods have been applied to get mechanically stronger, more thermally stable and chemically resistant polymer coatings. However, there is no existing approach that could effectively characterize the degree or depth of cross‐linking for thin polymer films. The objective of this work is to use atomic force microscopy to characterize cross‐linking depth in a precise way. Hyperthermal hydrogen bombardment‐induced cross‐linking was employed as a cross‐linking method and the depth of cross‐linking was estimated via local change of the elastic modulus along the sample cross‐section with precise force measurement and high spatial resolution. It is found that the cross‐linking depth is closely related to the chemical composition of thin films. Understanding the depth of cross‐linking is vital for a broad range of applications. It is believed that the developed technique is also applicable for studying other cross‐linkable materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41493.     

Untersuchung des Prall‐ und Druckverhaltens feuchter γ‐Al2O3‐Granulate

The material behavior of dominant elastic‐plastic γ‐Al₂O₃ granules has been experimentally studied by means of quasi static compression tests and dynamic impact tests until fracture. The obtained distributions of breakage velocity and specific breakage energy are compared. Thus, velocity‐dependent influences at stressing like viscous behaviour can be derived. Additionally, the influence of particle size and moisture content are investigated.     

Oxidative elimination of cyanotoxins: comparison of ozone, chlorine, chlorine dioxide and permanganate

As the World Health Organization (WHO) progresses with provisional Drinking Water Guidelines of 1 microg/L for microcystin-LR and a proposed Guideline of 1 microg/L for cylindrospermopsin, efficient treatment strategies are needed to prevent cyanotoxins such as these from reaching consumers. A kinetic database has been compiled for the oxidative treatment of three cyanotoxins: microcystin-LR (MC-LR), cylindrospermopsin (CYN), and anatoxin-a (ANTX) with ozone, chlorine, chlorine dioxide and permanganate. This kinetic database contains rate constants not previously reported and determined in the present work (e.g. for permanganate oxidation of ANTX and chlorine dioxide oxidation of CYN and ANTX), together with previously published rate constants for the remaining oxidation processes. Second-order rate constants measured in pure aqueous solutions of these toxins could be used in a kinetic model to predict the toxin oxidation efficiency of ozone, chlorine, chlorine dioxide and permanganate when applied to natural waters. Oxidants were applied to water from a eutrophic Swiss lake (Lake Greifensee) in static-dose testing and dynamic time-resolved experiments to confirm predictions from the kinetic database, and to investigate the effects of a natural matrix on toxin oxidation and by-product formation. Overall, permanganate can effectively oxidize ANTX and MC-LR, while chlorine will oxidize CYN and MC-LR and ozone is capable of oxidizing all three toxins with the highest rate. The formation of trihalomethanes (THMs) in the treated water may be a restriction to the application of sufficiently high-chlorine doses.     

Low-temperature formation and degradation of chlorinated benzenes, PCDD and PCDF in dust from steel production

Dust from thermal processes may catalytically enhance the formation of chlorinated aromatic compounds under oxygen-rich conditions. The activities of two dust samples from electric arc furnaces and one from iron ore-based steelmaking (oxygen converter) were investigated in a laboratory experiment. The dust samples were heated at 300 degrees C for 2 h in an air atmosphere. The concentrations of chlorinated benzenes did not change greatly upon heating, while the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans decreased. The addition of copper in parallel runs resulted in a substantial increase in the concentration of chlorinated benzenes, thus indicating that the experimental setup was suitable for the evaluation of low-temperature catalysis. The outcome of the experiment seems to suggest that results cannot easily be extrapolated between different thermal and metallurgical processes. Some measures to reduce emissions, such as inhibition of catalytic activity and rapid cooling, could possibly be counterproductive when applied to off-gases from the steelmaking processes investigated here.