Lignocellulosic Ethanol: The Path to Market

The cost effective production of transport fuels from biomass is essential if the EU aspiration to substitute 10% of transport fuels with sustainable alternatives by 2020 is to be met. The hope, voiced by the Parliament’s Industry and Energy Committee, is that at least 40% of the 2020 target will come from second-generation biofuels, and therein lies the challenge: second-generation conversion technologies are not yet commercial. Multiple pathways are being investigated around the globe, but dominant pathways have yet to emerge and business models have yet to be proven. Nevertheless, expectations are running high and there has been significant investment in R&D in the US, Europe and Asia. The production of ethanol from lignocellulosic biomass is commercially and environmentally one of the most promising options, and in 2007 the US Department of Energy (DOE) provided more than US$1 billion toward lignocellulosic ethanol (LE) projects. Their goal was to make the fuel cost competitive at$1.33 per gallon, when deployed at scale, by 2012. The majority of studies also suggest that LE will result in superior greenhouse gas savings compared to ethanol produced from starch. Despite favourable predictions for cost and environmental performance, market deployment requires practical and plausible development paths that are able to support progress from existing small-scale demonstration plant to large industrial installations. Moreover, these development paths must be sufficiently attractive to persuade developers and investors that lignocellulosic ethanol remains an opportunity worth pursuing

Solutions to the reconstruction problem in asymptotic safety

Starting from a full renormalised trajectory for the effective average action (a.k.a. infrared cutoff Legendre effective action) $\Gamma_k$, we explicitly reconstruct corresponding bare actions, formulated in one of two ways. The first step is to construct the corresponding Wilsonian effective action $S^k$ through a tree-level expansion in terms of the vertices provided by $\Gamma_k$. It forms a perfect bare action giving the same renormalised trajectory. A bare action with some ultraviolet cutoff scale $\Lambda$ and infrared cutoff $k$ necessarily produces an effective average action $\Gamma^\Lambda_k$ that depends on both cutoffs, but if the already computed $S^\Lambda$ is used, we show how $\Gamma^\Lambda_k$ can also be computed from $\Gamma_k$ by a tree-level expansion, and that $\Gamma^\Lambda_k\to\Gamma_k$ as $\Lambda\to\infty$. Along the way we show that Legendre effective actions with different UV cutoff profiles, but which correspond to the same Wilsonian effective action, are related through tree-level expansions. All these expansions follow from Legendre transform relationships that can be derived from the original one between $\Gamma^\Lambda_k$ and $S^k$.Comment: 32 page

Planetary benchmarks

Design criteria and technology requirements for a system of radar reference devices to be fixed to the surfaces of the inner planets are discussed. Offshoot applications include the use of radar corner reflectors as landing beacons on the planetary surfaces and some deep space applications that may yield a greatly enhanced knowledge of the gravitational and electromagnetic structure of the solar system. Passive retroreflectors with dimensions of about 4 meters and weighing about 10 kg are feasible for use with orbiting radar at Venus and Mars. Earth-based observation of passive reflectors, however, would require very large and complex structures to be delivered to the surfaces. For Earth-based measurements, surface transponders offer a distinct advantage in accuracy over passive reflectors. A conceptual design for a high temperature transponder is presented. The design appears feasible for the Venus surface using existing electronics and power components

Uinta Ground Squirrel Demography: Is Body Mass a Better Categorical Variable Than Age?

We compared the relative impact of age and body mass on fecundity and survival in a population of Uinta ground squirrels, and modeled the population using bodymass classes as stage categories in Lefkovitch stage transition matrices. Body mass was a better predictor of survival than was age, and was nearly as good a predictor of litter size. Mass-based stage transition matrices provided results similar to age-based transition matrices, but also indicated that larger and subsequently more fecund young were a consequence of a population reduction. We believe that mass-based analysis of ground squirrel populations is a viable alternative to traditional age-based analyses. Body mass is easy to measure in small-mammal populations and is linked to a variety of life-history characteristics

Preliminary comparison of 3.5-cm and 12.6-cm wavelength continuous wave observations of Mars

Radar observations of Mars at Goldstone in 1990 were conducted by transmitting pure sinusoidal signals at 3.5-cm wavelengths and receiving the Doppler-spread echoes from Mars at Earth. Radar transmissions were circularly polarized and the echoes recorded in two senses: depolarized and polarized. Latitudes of the subradar points are between 3.5 deg and 11.1 deg S; longitude coverage is discontinuous. The observed depolarized and polarized echo total cross-sections and their ratios for two wavelengths were compared and discussed