Galilei covariance and (4,1) de Sitter space

A vector space G is introduced such that the Galilei transformations are considered linear mappings in this manifold. The covariant structure of the Galilei Group (Y. Takahashi, Fortschr. Phys. 36 (1988) 63; 36 (1988) 83) is derived and the tensor analysis is developed. It is shown that the Euclidean space is embedded the (4,1) de Sitter space through in G. This is an interesting and useful aspect, in particular, for the analysis carried out for the Lie algebra of the generators of linear transformations in G.Comment: Late

Hydrogen storage in the form of metal hydrides

Reversible reactions between hydrogen and such materials as iron/titanium and magnesium/ nickel alloy may provide a means for storing hydrogen fuel. A demonstration model of an iron/titanium hydride storage bed is described. Hydrogen from the hydride storage bed powers a converted gasoline electric generator

An unpublished interview with Paulo Freire: radical pedagogy & social transformation

Pulling together the inedited works by Paulo Freire in the XXI century shows us how his works are up-to-date with current issues in the field. Most of his works have been disseminated all over the World, as those of the greatest educator of all times; however, his simplicity and outspoken voice is unique and cannot be reproduce in a simple manner. This is possibly why many writers use his citations, instead of paraphrasing his writings. Therefore, this paper represents another attempt to focus on his own voice and perspective on some of the questions raised by students three decades ago, that had never reach a broad audience but are nevertheless still in the minds of many students who are today interested in his work. The paper presents a short unpublished interview with Freire in 1988, when he talks about theoretical affiliation, critiques and the objectives of his works. In a conversation format the interview is a re-encounter between Paulo Freire and his former student Carmen de Mattos