1,833 research outputs found
Large negative magnetoresistance in a ferromagnetic shape memory alloy : Ni_{2+x}Mn_{1-x}Ga
5% negative magnetoresistance (MR) at room temperature has been observed in
bulk Ni_{2+x}Mn_{1-x}Ga. This indicates the possibility of using
Ni_{2+x}Mn_{1-x}Ga as magnetic sensors. We have measured MR in the
ferromagnetic state for different compositions (x=0-0.2) in the austenitic,
pre-martensitic and martensitic phases. MR is found to increase with x. While
MR for x=0 varies almost linearly in the austenitic and pre-martensitic phases,
in the martensitic phase it shows a cusp-like shape. This has been explained by
the changes in twin and domain structures in the martensitic phase. In the
austenitic phase, which does not have twin structure, MR agrees with theory
based on s-d scattering model.Comment: 3 pages, 3 figures, Appl. Phys. Lett 86, 202508 (2005
CDM afforestation and reforestation baseline methodologies: An analysis of the submission and approval process
Afforestation and Reforestation (A/R), also widely termed LULUCF have been an important field of conflict in the Clean Development Mechanism (CDM) of the Kyoto Protocol. The first methodology for A/R projects has been submitted only by October 2004 and the first project was registered only in November 2006, two years after the first project in the energy sector. Like energy efficiency and transportation methodologies, A/R methodologies also suffer high rejection rate. 20 A/R CDM methodologies evaluated by the CDM Executive Board have been analyzed in this paper with respect to their approval history. On an average it took 4-5 months for approval of A/R methodologies in contrast to the long approval time taken in case of other methodologies (9-10 months). Most methodologies has been rejected because of not properly defining land eligibility, incomplete baseline scenario selection, lack of methods to prove additionality and insufficient treatment of uncertainties. --
- …