Ana C. M. Ferreira

A vanishing theorem in twisted de Rham cohomology

We prove a vanishing theorem for the twisted de Rham cohomology of a compact manifold.

Quaternionic Heisenberg groups as naturally reductive homogeneous spaces

In this note, we describe the geometry of the quaternionic Heisenberg groups from a Riemannian viewpoint. We show, in all dimensions, that they carry an almost

Tangent Lie Groups are Riemannian Naturally Reductive Spaces

3

Contact angle measurement of SAC 305 solder: numerical and experimental approach

-contact metric structure which allows us to define the metric connection that equips these groups with the structure of a naturally reductive homogeneous space. It turns out that this connection, which we shall call the canonical connection because of its analogy to the

On solving the profit maximization of small cogeneration systems

3

Dirichlet principal eigenvalue comparison theorems in geometry with torsion

-Sasaki case, preserves the horizontal and vertical distributions and even the quaternionic contact structure of the quaternionic Heisenberg groups. We focus on the

Shedding light on important mentorship relationships issues in advanced engineering education

7

Modeling a stirling engine for cogeneration applications

-dimensional case and prove that the canonical connection can also be obtained by means of a cocalibrated

Optimal design of micro-turbine cogeneration systems for the portuguese buildings sector

G_2

Non-existence of orthogonal complex structures on the round 6-sphere

structure. We then study the spinorial properties of this group and present the noteworthy fact that it is the only known example of a manifold which carries generalized Killing spinors with three different eigenvalues.