Quantifying the limits of HANPP and carbon emissions which prolong total species well-being

Anthropogenic climate and land-use change are leading to irreversible losses of global biodiversity, upon which ecosystem functioning depends. Since total species' well-being depends on ecosystem goods and services, man must determine how much net primary productivity (NPP) may be appropriated and carbon emitted so as to not adversely impact this and future generations. In 2005, man ought to have only appropriated 9.72 Pg C of NPP, representing a factor 2.50, or 59.93%, reduction in human-appropriated NPP in that year. Concurrently, the carbon cycle would have been balanced with a factor 1.26, or 20.84%, reduction from 7.60 Gt C/year to 5.70 Gt C/year, representing a return to the 1986 levels. This limit is in keeping with the category III stabilization scenario of the Intergovernmental Panel for Climate Change. Projecting population growth to 2030 and its associated basic food requirements, the maximum HANPP remains at 9.74 ± 0.02 Pg C/year. This time-invariant HANPP may only provide for the current global population of 6.51 billion equitably at the current average consumption of 1.49 t C per capita, calling into question the sustainability of developing countries striving for high-consuming country levels of 5.85 t C per capita and its impacts on equitable resource distribution. © Springer Science+Business Media B.V. 2009.

Smooth thin film C/diamond membranes with controllable optical band gaps

Mixed phase carbon-diamond films which consist of small grain diamond in an a:C matrix were deposited on polished Si using a radio frequency CH4 Ar plasma CVD deposition process. Ellipsometry, surface profilometry, scanning electron microscopy (SEM) and spectrophotometry were used to analyse these films. Film thicknesses were typically 50-100 nm with a surface roughness of ± 30 A ̊ over centimetre length scans. SEM analysis showed the films were smooth and pinhole free. The Si substrate was etched using backside masking and a directional etch to give taut carbon-diamond membranes on a Si grid. Spectrophotometry was used to analyse the optical properties of these membranes. Band gap control was achieved by varying the dc bias of the deposition process. Band gaps of 1.2 eV to 4.0 eV were achieved in these membranes. A technique for controlling the compressive stress in the films, which can range from 0.02 to 7.5 GPa has been employed. This has allowed the fabrication of thin, low stress, high band gap membranes that are extremely tough and chemically inert. Such carbon-diamond membranes seem promising for applications as windows in analytical instruments. © 1992.