On Sp(2) and Sp(2)· Sp(1) -structures in 8-dimensional vector bundles

Let ξ be an oriented 8-dimensional vector bundle. We prove that the structure group SO(8) of ξ can be reduced to Sp(2) or Sp(2) · Sp(1) if and only if the vectorbundle associated to ξ via a certain outer automorphism of the group Spin(8) has 3 linearly independent sections or contains a 3-dimensional subbundle. Necessary and sufficient conditions for the existence of an Sp(2)-structure in ξ overa closed connected spin manifold of dimension 8 are also given in terms of characteristic classes

Mechanical reinforcement effects of carbon nanotube polymer composites

THESIS 7415The effect of varying current density and pressure during arc-generation on the yield and purity of multi walled carbon nanotube containing carbon soot has been studied in this work. Various soots were produced and characterised qualitatively using transmission electron microscopy and quantitatively using electron paramagnetic resonance and thermal gravimetric analysis. It was found that both yield and purity increase as current density and pressure are increased

On Sp(2) and Sp(2)· Sp(1) -structures in 8-dimensional vector bundles

Let ξ be an oriented 8-dimensional vector bundle. We prove that the structure group SO(8) of ξ can be reduced to Sp(2) or Sp(2) · Sp(1) if and only if the vectorbundle associated to ξ via a certain outer automorphism of the group Spin(8) has 3 linearly independent sections or contains a 3-dimensional subbundle. Necessary and sufficient conditions for the existence of an Sp(2)-structure in ξ overa closed connected spin manifold of dimension 8 are also given in terms of characteristic classes