Algorithms for Visualizing Phylogenetic Networks

We study the problem of visualizing phylogenetic networks, which are extensions of the Tree of Life in biology. We use a space filling visualization method, called DAGmaps, in order to obtain clear visualizations using limited space. In this paper, we restrict our attention to galled trees and galled networks and present linear time algorithms for visualizing them as DAGmaps.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

A comparative assessment of biomass ash preparation methods using X-ray fluorescence and wet chemical analysis

X-ray fluorescence (XRF) spectroscopy is a rapid method used to determine the composition of biomass ash, but the accuracy of the method is sensitive to various factors including ash preparation methods. In this study different types of biomass ash were examined by using wet chemical analysis (WCA) and compared with the respective XRF results. The biomass ash was initially prepared in accordance with the European Standard method at 550 °C. At this low combustion temperature the amount of residual unburned carbon is significant. To eliminate this, the ashes were heated at higher temperatures: a batch of twenty biomass ashes were heated at 850 °C and a batch of five heated to 815 °C. At these higher temperatures there may be loss of inorganic components by vaporisation. Variation in these effects may lead to unreliable results. The relationship between XRF and WCA results are given by regression equations. The ashes processed at 815 °C show better agreement between the two analysis methods

Energy potential of native shrub species in northern Spain

This paper we present an energy review of the waste generated by shrub species in soils of low fertility for use as fuel in a power plant. The residues analysed belong to the species: Rhamus alaternus, Ulex europaeus, Prunus spinosa, Smilax aspera, Erica sp., Rubus ulmifolius, and Pteridium aquilinum. Gross calorific value (GCV), net calorific value (NCV), density, elementary chemical analysis, moisture content, percentage of ash, productivity, energy density and FVI (fuel value index) have been measured. These parameters have been determined for three levels of moisture (maximum, medium and minimum). At medium moisture level, the residues of U. europaeus are those that reach the greatest FVI, 20,000. In the other extreme is the P. aquilinum with an FVI of 403. The average productivity of waste, in t ha 1, of each species has been determined in order to know how much energy is stored per hectare. U. europaeus and P. spinosa are the species which accumulate more energy per hectare, with similar values of around 81 MJ ha 1 yr 1 and installed power of 2.59Wha 1. The energy recovery of the waste in a thermal power plant would generate an annual revenue of 14.6 MV, taking into account that 40% of the forest land covered by shrub in Cantabria is used for this purpose

Effect of biomass leaching on H2 production, ash and tar behavior during high temperature steam gasification (HTSG) process

The effect of biomass water leaching on H 2 production, as well as, prediction of ash thermal behavior and formation of biomass tar during high temperature steam gasification (HTSG) of olive kernel is the main aim of the present work. Within this study raw olive kernel samples (OK 1 , OK 2 ) and a pre-treated one by water leaching (LOK 2 ) were examined with regard to their ash fouling propensity and tar concentration in the gaseous phase. Two temperatures (T = 850 and 950 °C) and a constant steam to biomass ratio (S/B = 1.28) were chosen in order to perform the steam gasification experiments. Results indicated that considering the samples' ash thermal behavior, it seemed that water leaching improved the fusibility behavior of olive kernel; however, it proved that water leaching does not favour tar steam reforming, while at the same time decreases the H 2 yield in gas product under air gasification conditions, due to possible loss of the catalytic effect of ash with water leaching. © 2009