The effects of filler size on the properties of thermoplastic polyolefin blends

The effects of filler size on the properties of a thermoplastic polyolefin (TPO) blend were examined by using wollastonite and talc with particle sizes ranging from 1.2 to 40 μm. While addition of filler produced significant changes in the mechanical properties of the blend, filler size affected only impact strength. However, filler size, filler coating, and injection speed had a major effect on the surface properties of the blend. Faster injection produced denser “shear zone layers” which exhibited better scratch resistance and poorer paint adhesion than those obtained with slower injection. Scartch resistance and paint adhesion also decreased with increasing filler particle size. Filler coatings altered the scratch and adhesion properties of the polypropylene (PP) blends.     

On multivariate order statistics. Application to ranked set sampling

Two new concepts of order statistics for multivariate samples are introduced. In one of the versions it turns out that not every multivariate order statistic is present in every sample. These order statistics have application in multivariate ranked set sampling and can be used to generate broad classes of multivariate densities in the sense of Jones. In this case the likelihood for the sample values and their corresponding ranks can be calculated based on the conditional density of a multivariate order statistics given its sample value, and such that its integral gives the probability for the multivariate order statistics under discussion to be observed. An alternative version of multivariate order statistics is also introduced, for which multivariate order statistics are always well defined and expressions for their marginal densities are derived. Since these multivariate order statistics are tailor made for multivariate ranked set sampling, their densities allow for parameter inference based on ranked set sampling. Some simulations show that both multivariate order statistics densities can be used with advantage with respect to simple random sampling.     

Reversible acetonitrile-induced inactivation/activation of thermolysin

Thermolysin is catalytically inactive in mixtures of 10-15 % acetonitrile in aqueous buffer. Unexpectedly, dilution of the inactive enzyme with acetonitrile leads to complete recovery of the catalytic activity in a similar way to dilution with aqueous buffer. Circular dichroism and fluorescence studies of thermolysin in the same solvent mixtures reveal discontinuous changes in the overall secondary and tertiary protein structure that correlate well with the reversible differences in catalytic activity. The spectra on either side of the minimum activity point are different from each other, a fact indicating that the enzyme may be able to access two active conformations which are thermodynamically stable in different solvent environments.     

Investigating the Relations used in Conceptual Combination

How do people understand noun–noun compounds such as volcano science and pear bowl? In this paper, we present evidence against one approach to noun–noun compounds, namely that of arranging the meanings of compounds into a small, finite taxonomy of general semantic relations. Using a typical relation taxonomy, we conducted an experiment examining how people classify compounds into the taxonomy’s relation categories. We found that people often select not one but several relations for each compound; for example, people classify coffee stain as coffee MAKES stain, stain MADE OF coffee, coffee CAUSES stain and stain DERIVED FROM coffee. A natural metric for relational similarity follows from our experimental data; we found that using cluster analysis to group compounds’ interpretations with respect to this metric produced groupings that were different from the original taxonomic categories, suggesting that there is more than one way to classify the meanings of compounds. We also found that compounds which had similar constituent concepts tended to be interpreted with similar relations, indicating that the intrinsic properties of a compound’s constituent concepts help determine how that compound is interpreted. Such findings are problematic for taxonomic theories of conceptual combination     

Augmented geophysical data interpretation through automated velocity picking in semblance velocity images

Velocity picking is the problem of picking velocity–time pairs based on a coherence metric between multiple seismic signals. Coherence as a function of velocity and time can be expressed as a 2D color semblance velocity image. Currently, humans pick velocities by looking at the semblance velocity image; this process can take days or even weeks to complete for a seismic survey. The problem can be posed as a geometric feature-matching problem. A feature extraction algorithm can recognize islands (peaks) of maximum semblance in the semblance velocity image: a heuristic combinatorial matching process can then be used to find a subset of peaks that maximizes the coherence metric. The peaks define a polyline through the image, and coherence is measured in terms of the summed velocity under the polyline and the smoothness of the polyline. Our best algorithm includes a constraint favoring solutions near the median solution for the local area under consideration. First, each image is processed independently. Then, a second pass of optimization includes proximity to the median as an additional optimization criterion. Our results are similar to those produced by human experts. Accepted: 15 June 2001     

Personal hypothesis testing: The role of consistency and self-schema.

We report the results of two experiments that examined the way individuals test hypotheses about themselves. Both experiments were based on the work of Snyder (e.g., Snyder, 1981; Snyder & Skrypnek, 1981), which suggests that individuals have a confirmatory bias when testing hypotheses about others and about themselves. In Experiment 1, we examined the extent to which this bias toward confirmation persists when a negative (e.g., depression) or nonconsistent (not consistent with the individual's evaluation of him- or herself) personal hypothesis is tested. Results suggest that the negative or positive nature of a personal hypothesis does not directly influence the way individuals test their hypothesis. However, the way individuals tested personal hypotheses was influenced by hypothesis consistency. In Experiment 2, we examined the relation of a cognitive schematic variable (i.e., vulnerability for depression) and hypothesis testing. Results suggest that vulnerability is related to the way individuals test a personal hypothesis about depression. Vulnerable, low-depression participants were confirmatory when testing a depression hypothesis, whereas nonvulnerable, low-depression participants were disconfirmatory. We discuss implications for counseling and future directions for research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)