Enhanced mobility and increased gas sorption capacity in thin film and nanoconduit confined polymers

Poly(tert butyl acrylate) (PTBA) is found to exhibit enhanced mobility when spun cast into thin films or impregnated into cylindrical anodic aluminum oxide (AAO) nanoscale pores. In a thin film configuration, the glass transition temperature of 20 nm thick PTBA is found to decrease almost 20 °C compared to the bulk. Consistent with this mobility increase, an increased volume fraction of interphase polymer leads to at least a 2.4 times viscosity reduction when PTBA is impregnated in 100 nm pores versus 200 nm pores. Such increases in mobility result in a 15‐fold increase in CO₂ permeability for an AAO confined geometry compared to a bulk film. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 434–441, 2010     

Robustness to nonnormality of some transformations of the sample correlation coefficient

In this paper, some of the familiar transformations of r are examined for their robustness to nonnormality. General results are given for any parent population f(x, y) and any general transformation g(r) of r. Two types of parent populations are considered for exemplification: The bivariate Edgeworth series distribution and the truncated bivariate normal distribution. The effects of nonnormality are assessed through the parameters μ′₁, μ₂, γ₁, γ₂. Tables are provided comparing these quantities against their bivariate normal counterparts.     

Factors to be considered in the preparation of single and multi-element standards for inductively coupled plasma optical emission spectrometry.

The problems encountered with the production of single and multi-element inductively coupled plasma (ICP) optical emission spectrometry (OES) standards are reviewed. Purity, stability and characterization of starting materials, water and acids have profound effects on the quality of these standards. The trace level contaminants and the form of the starting materials can result in serious analytical errors. Long-term stability of the ICP-OES standard, dependent in part on the storage container composition, plays an important role in the accuracy of ICP-OES calibration. The relationship between inter-element correction factors and the quality of ICP-OES standards is discussed. Finally, some of the factors that must be considered during the manufacture of multi-element standards for instrument calibration, universal and customer-specific applications are delineated.     

On the compounded bivariate Poisson distribution: A unified treatment

A unified treatment is presented here of compounding with the bivariate Poisson distribution. Exploiting the exponential nature of its probability generating function, it is shown that the pgf of the compound distribution is the moment generating function of the compounding random variable. This relationship leads to rather interesting general results. Particularly, the development of the conditional distribution is simplified. Four cases are presented in detail.     

On the errors of misclassification based on dichotomous and normal variables

Summary The distribution of the errors of misclassification in procedures based on dichotomous and normal variables is derived. The expressions forE(e ₁₂) andE(e ₂₁) are also obtained. The results in the paper extend those of Chang and Afifi (1974,J. Amer. Statist. Ass.,69, 336–339), using the earlier papers due to John (1961,Ann. Math. Statist.,32, 1125–1144), Subrahmaniam and Chinganda (1978,J. Statist. Plann. Inf.,2, 79–91).     

Functions of a quaternion variable which are gradients of real-valued functions

We consider the collection of functions of one quaternion variable which can be expressed asG(Y) whereY is a real-valued quaternion function andG is a differential operator which corresponds to the gradient of real variable theory. Integral theorems for such functions are given, together with necessary and sufficient conditions for a function to be a gradient function, in terms of its Frechet derivative. The extended complex analytic functions, the Fueter functions, and the momentum-energy density functions are seen to be gradient functions which correspond to biharmonic, harmonic, and wave functions respectively.     

On the performance of some statistics in discriminant analysis based on covariates

In this paper we study the behavior of three statistics suggested for testing the hypothesis, H₀ : μ₁ = μ₂, in the two sample case, in the presence of covariables. Power comparisons are made in the case when δ₂, the difference of the mean vectors in the covariates, is not equal to zero. This extends an earlier paper of the authors [Sanklya Ser. B35 51–78], where δ₂ was assumed to be equal to zero. The results reiterate those obtained in the above cited paper that for low observed values of D_q² one would use t₂ otherwise t₃ would be recommended. The statistic t₁ does not seem to be appropriate for testing this hypothesis.