Molecular weight-viscosity relationship for amylopectin,a highly branched polymer

Summary Rate of acid hydrolysis of amylopectin is discussed from molecular weight variation; a two step mechanism is found. The highly branched amylopectin fractions obtained by partial acid hydrolysis allow experimental determination of Mark-Houwink's law exponents. Theoretical and experimental a values are compared.Laboratoire Propre du C.N.R.S., associé à l'Université Scientifique et Médicale de Grenoble     

Developmental changes in the understanding of pictorial representations of sound.

Two studies examined understanding of pictures representing sound production among 112 3–6 yr olds. In Study 1, Ss labeled pictures as either showing sound or not; in Study 2, Ss chose which of a pair of pictures showed sound. Pictures varied as to the extent the representations were designed to be analogous to actual sound production in the environment. Different types of pictorial representation of sound were not equivalent in their ability to evoke a correct interpretation. Ss across the age range tested all understood the pictures that depicted postures associated with sound production in the environment. Pictures that relied on conventional or arbitrary representations of sound, such as lines radiating from a mouth, were less well understood by the younger Ss. Over the preschool years, however, there was substantial improvement in Ss' skill at interpreting these pictures. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vécu expérientiel et développement intellectuel et éthique chez la femme québécoise d'aujourd'hui.

Studied the role of experience in the intellectual and ethical development (IED) of women beginning a program of higher education in Quebec. Based on the assumption that recent changes in the role of women in society would affect this development, W. G. Perry's (1970) scale for the measurement of adult IED was modified accordingly and used as a basis for assessing the Ss' development. Human subjects: 22 female Canadian adults (23–65 yrs) (mean age 33.5 yrs) (newly registered university students from various disciplines) (10 were single, 9 were married, and 3 were divorced). Ss were divided into 3 age groups: 20–29 yrs, 30–44 yrs, and 45 yrs and over. Each S individually participated in a semiformal interview investigating her thoughts on "the role of women in society," and on "education and knowledge." Qualitative and quantitative analyses were performed on the results. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gel permeation chromatography of the xanthan gum using a light scattering detector

Summary This work gives the first gel permeation chromatogramms obtained on native xanthan using a refractometric and a light scattering detectors. Results of molecular weights distribution analysis give a polydispersity 1.2 for the native polymer and 1.7 for enzymic partially degraded polymer. The experimental conditions and chromatogramms interpretation are briefly discussed.Laboratoire Propre de C.N.R.S., associé à l'Université Scientifique et Médicale de Grenoble     

Multi-scale GEOBIA with very high spatial resolution digital aerial imagery: scale,texture and image objects

This study used geographic object-based image analysis (GEOBIA) with very high spatial resolution (VHR) aerial imagery (0.3 m spatial resolution) to classify vegetation, channel and bare mud classes in a salt marsh. Three classification issues were investigated in the context of segmentation scale: (1) a comparison of single- and multi-scale GEOBIA using spectral bands, (2) the relative benefit of incorporating texture derived from the grey-level co-occurrence matrix (GLCM) in classifying the salt marsh features in single- and multi-scale GEOBIA and (3) the effect of quantization level of GLCM texture in the context of multi-scale GEOBIA. The single-scale GEOBIA experiments indicated that the optimal segmentation was both class and scale dependent. Therefore, the single-scale approach produced an only moderately accurate classification for all marsh classes. A multi-scale approach, however, facilitated the use of multiple scales that allowed the delineation of individual classes with increased between-class and reduced within-class spectral variation. With only spectral bands used, the multi-scale approach outperformed the single-scale GEOBIA with an overall accuracy of 82% vs. 76% (Kappa of 0.71 vs. 0.62). The study demonstrates the potential importance of ancillary data, GLCM texture, to compensate for limited between-class spectral discrimination. For example, gains in classification accuracies ranged from 3% to 12% when the GLCM mean texture was included in the multi-scale GEOBIA. The multi-scale classification overall accuracy varied with quantization level of the GLCM texture matrix. A quantization level of 2 reduced misclassifications of channel and bare mud and generated a statistically higher classification than higher quantization levels. Overall, the multi-scale GEOBIA produced the highest classification accuracy. The multi-scale GEOBIA is expected to be a useful methodology for creating a seamless spatial database of marsh landscape features to be used for further geographic information system (GIS) analyses.     

Non-destructive ultrasonic velocimetry for central region velocity fields in turbulent Rayleigh-Bénard convection of mercury

A non-destructive method of measuring flow field of opaque fluids is presented for turbulent convection of liquid metal mercury. Two important properties of the turbulent state, namely 2D velocity profiles and energy spectrum, are successfully measured for Rayleigh-Bénard convection of mercury by using ultrasonic Doppler velocimetry. A few key techniques for the method are also explained.     

Synthesis and characterization of srilankite nanowires

We describe the synthesis and characterization of srilankite (Ti2ZrO6) nanowires. The nanowires are produced via hydrothermal synthesis with a TiO2/ZrO2 mixture under alkaline conditions. The zirconium titanate nanowires have median diameters of 60 nm and median lengths of 800 nm with the (022) axis along the length of the nanowire. Electron microscopy, energy dispersive X-ray spectroscopy, powder X-ray diffraction, and electron diffraction are used to characterize the phases and compare nanowires produced with varying molar ratios of Ti and Zr. Electron diffraction patterns produced from single nanowires show highly crystalline nanowires displaying a compositional-ordering superlattice structure with Zr concentrated in bands within the crystal structure. This is in contrast to naturally occurring bulk srilankite where Zr and Ti are randomly substituted within the crystal lattice. Streaking is observed in the electron diffraction patterns suggesting short-range ordering within the superlattice structure.     

Factors affecting the solubility of gypsum. The effect of lime and temperature in different media

The effect of lime on the solubility of gypsum in water and in sodium hydroxide solution at 30, 60 and 100°C has been studied turbidimetrically and by means of X-ray diffraction analysis. Lime depressed the solubility of gypsum in water only slightly at 30°C and a rise of temperature minimised its effect until its complete elimination. In the absence of alkali the minimum sulphate ion concentration in a supersaturated lime solution and at temperatures in the range 30–100°C is about 1.2gdm⁻³. In sodium hydroxide solution neither lime nor temperature played a significant role and the solubility of gypsum was clearly promoted. At temperatures in the range 30–100°C, 0.5g of gypsum dissolved in 100cm³ of 0.2MNaOH solution.