Nuclear acoustical resonance in aluminum in the intermediate temperature region

1978 ◽  
Vol 18 (3) ◽  
pp. 1508-1513 ◽  
Author(s):  
E. J. Ozimek ◽  
D. K. Hsu ◽  
R. G. Leisure
Keyword(s):  
Temperature Region ◽  
Intermediate Temperature

Three-dimensional small-angle neutron scattering of shear-induced phase separation in a dynamically asymmetric polymer mixture

2006 ◽  
Vol 39 (6) ◽  
pp. 878-888 ◽  
Author(s):  
Satoshi Koizumi ◽  
Jun-ichi Suzuki
Keyword(s):  
Phase Separation ◽  
Neutron Scattering ◽  
Temperature Region ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Three Dimensional ◽  
Shear Velocity ◽  
Intermediate Temperature ◽  
Polymer Mixture ◽  
Vinyl Methyl Ether

A polymer mixture of polystyrene (PS)/poly(vinyl methyl ether) (PVME) has been investigated by using a three-dimensional small-angle neutron scattering (3D-SANS) method. PS and PVME exhibit a large difference in the glass transition temperatureTg. Therefore, dynamical asymmetry is strongly enhanced in an intermediate temperature region between theTgvalues of neat PS and PVME. In the intermediate temperature region, a shear deformation was imposed on the polymer mixture to enhance the concentration fluctuations,i.e.shear-induced phase separation. By rotating the film specimen, which was rapidly quenched after deformation, 3D-SANS due to shear-induced phase separation was observed successfully. In theqx=qyplane of the sample coordinate system, whereqis a component of scattering vectorq, it was possible to observe SANS of `double-lobe' shape, with the minor axes of the lobes inclined towardsqx=qy, whereqx,qyandqz, denote the shear, velocity gradient and vorticity directions in reciprocal space, respectively. Abnormal `butterfly' scattering was observed in a section cut through the 3D-SANS in theqxqzplane. The 3D-SANS thus obtained is discussed in comparison with a model of dynamical coupling between stress and diffusion.

Thermogravimetric analysis of Ontario limestones and dolomites. II. Reactivity of sulfur dioxide with calcined samples

1970 ◽  
Vol 48 (19) ◽  
pp. 2979-2982 ◽  
Author(s):  
R. K. Chan ◽  
K. S. Murthi ◽  
D. Harrison
Keyword(s):  
Thermogravimetric Analysis ◽  
Sulfur Dioxide ◽  
Grain Boundaries ◽  
Temperature Region ◽  
Room Temperature ◽  
Intermediate Temperature ◽  
Controlled Atmosphere ◽  
Absorption Region ◽  
Fast Absorption

Thermogravimetric analysis was done for representative calcined samples of Ontario limestones and dolomites in a 5% SO2 controlled atmosphere. The SO2 absorption vs. temperature curves showed three distinct regions. (i) A unimolecular chemisorption of SO2 at room temperature. (ii) An intermediate temperature region between 200–450 °C where absorption of SO2 was due to increased rate of SO2 diffusion into the interior of CaO via grain boundaries. When the surfaces of these internal spaces were almost fully occupied the rate of SO2 absorption decreased. Further absorption was due to diffusion of SO2 into CaO lattice, which was a much slower process. (iii) A fast absorption region between 500–700 °C, where a disproportionation of CaSO3 into CaSO4 and CaS took place which effectively broke down the original CaO structure to expose fresh layers of CaO. The amount of SO2 absorption after 1 h at 745 °C corresponded to approximately 80% conversion of CaO to mainly CaSO4 and CaS and smaller amount CaSO3.Finally, the calculations showed that the reaction of SO2 with CaO was more exothermic than the reaction of SO2 with MgO, which accounted for the faster rate of the former.

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