A novel reforming method for hydrogen production from biomass steam gasification

In this work, an experimental study of biomass gasification in different operation conditions has been carried out in an updraft gasifier combined with a porous ceramic reformer. The effects of gasifier temperature, steam to biomass ratio (S/B), and reforming temperature on the gas characteristic parameters were investigated with and without porous ceramic filled in reformer. The results indicated that considerable synergistics effects were observed as the porous ceramic was filled in reformer leading to an increase in the hydrogen production. With the increasing gasifier temperature varying from 800 to 950 °C, hydrogen yield increased from 49.97 to 79.91 g H₂/kg biomass. Steam/biomass ratio of 2.05 seemed to be optimal in all steam-gasification runs. The effect of reforming temperature for water-soluble tar produced in porous ceramic reforming was also investigated, and it was found that the conversion ratio of total organic carbon (TOC) contents is between 71.08% and 75.74%.     

High efficient conversion of CO2-rich bio-syngas to CO-rich bio-syngas using biomass char: a useful approach for production of bio-methanol from bio-oil

A novel approach for high efficient conversion of the CO₂-rich bio-syngas into the CO-rich bio-syngas was carried out by using biomass char and Ni/Al₂O₃ catalyst, which was successfully applied for production of bio-methanol from bio-oil. After the bio-syngas conditioning, the CO₂/CO ratio prominently dropped from 6.33 to 0.01-0.28. The maximum CO yield in the bio-syngas conditioning process reached about 1.96 mol/(mol CO₂) with a nearly complete conversion of CO₂ (99.5%). The performance of bio-methanol synthesis was significantly improved via the conditioned bio-syngas, giving a maximum methanol yield of 1.32 kg/(kg_catalyst h) with a methanol selectivity of 99%. Main reaction paths involved in the bio-syngas conditioning process have been investigated in detail by using different model mixture gases and different carbon sources.     

A new approach to define optimized range of medium composition for enhancement of hairy root production in fed-batch process

This work proposes a new methodology to identify the best medium concentrations for fed-batch production of hairy root using Datura innoxia as a model. Firstly, the role of each component on the growth rate is investigated separately. Then, an experimental design allows refining the optimization studying the interactions between the major species. The result analysis let to define concentration range optimized for fed-batch process. The work novelties lie in two aspects. Firstly, concentrations have been kept constant during each run. Thus, biomass uptakes do not affect the optimization and the growth rate is maintained constant during the exponential phase. Secondly, the effects of salts are generally studied. In this work, the influences of each ion are investigated in order to avoid bias due to the counter-ion effects. Compared to the classical B₅ medium, the optimized medium shows a significant improvement leading to more than 80% increase of final biomass production.     

A probabilistic approach to estimating species pools from large compositional matrices

Abstract. Species pools are increasingly recognized as important controls of local plant community structure and diversity. While existing approaches to estimate their content and size either rely on phytosociological expert knowledge or on simple response models across environmental gradients, the proposed application of phytosociological smoothing according to Beals exploits the full information of plant co‐occurrence patterns statistically. Where numerous representative compositional data are available, the new method yields robust estimates of the potential of sites to harbour plant species. To test the new method, a large phytosociological databank covering the forested regions of Oregon (US) was subsampled randomly and evenly across strata defined by geographic regions and elevation belts. The resulting matrix of species presence/absence in 874 plots was smoothed by calculating Beals' index of sociological favourability, which estimates the probability of encountering each species at each site from the actual plot composition and the pattern of species co‐occurrence in the matrix. In a second step, the resulting lists of sociologically probable species were intersected with complete species lists for each of 14 geographical subregions. Species pools were compared to observed species composition and richness. Species pool size exhibited much clearer spatial trends than plot richness and could be modelled much better as a function of climatic factors. In this framework the goal of modelling species pools is not to test a hypothesis, but to bridge the gap between manageable scales of empirical observation and the spatio‐temporal hierarchy of diversity patterns.     

A pragmatic approach to the species problem from a paleontological perspective

The ideal scenario for paleontologists would be for the species they designate to be equivalent to the species recognized for modern animals, in the sense that they were formed as a result of the same evolutionary processes. This would mean, for example, that we could be confident that in combining extant and extinct taxa in phylogenetic analyses we would be dealing with equivalent operational taxonomic units. Notwithstanding the many thousands of pages that have been spent arguing over species concepts, the only concept that has won widespread acceptance for the designation of modern species is Mayr's Biological Species Concept (BSC).¹ In fact, whenever we complete a cladistic analysis, we assume reproductive isolation of our terminal taxa because otherwise their similarities could be the product of interbreeding rather than common ancestry. Fundamentally, we all behave as though the BSC is true.     

A change from phalanx to guerrilla growth form is an effective strategy to acclimate to sedimentation in a wetland sedge species Carex brevicuspis (Cyperaceae)

The rhizomatous sedge Carex brevicuspis can produce clumping ramets from shortened rhizomes (phalanx) and spreading ramets from elongated rhizomes (guerrilla) to form a combined clonal growth form. In this paper, changes in clonal growth and biomass allocation pattern of C. brevicuspis in response to sedimentation were studied. Four sedimentation depths (0, 3, 6, and 9 cm) were applied to 48 ramets in a randomized block design. Plants were harvested after 20 weeks. With increasing sedimentation depth, the proportion of spreading ramets to total ramets increased from 19.6% in 0 cm to 92.9% in 9 cm sedimentation treatments, whereas that of clumping ramets decreased from 80.4% to 7.1%, indicating a change of clonal growth form from phalanx to guerrilla as a response to sedimentation. With increasing sedimentation depth, biomass allocation to shoots and roots did not change, but rhizome mass ratio increased from 2.7% in 0 cm to 7.2% in 9 cm sedimentation treatments, suggesting that production of long rhizomes changes biomass allocation pattern. The results show that plasticity of clonal growth forms, by which more spreading ramets are produced, is an effective strategy to avoid sedimentation stress under our experimental conditions.     

A multivariate statistical approach to Centaurea classification using essential oil composition data of some species from Turkey

The composition of the essential oils of ten Centaurea species from Turkey, Centaurea aladaghensis, C. antiochia var. prealta, C. antitauri, C. babylonica, C. balsamita, C. cheirolepidoides, C. deflexa, C. iconiensis, C. lanigera, C. ptosimopappoides have been studied. Multivariate statistical analyses (Principal Component Analysis, Multidimensional Scaling, Hierarchical Cluster Analysis) applied to GC-MS data, seem to be very useful to investigate and establish the natural taxonomic delimitation of this very difficult genus. The groupings resulted independent from the ecological similarities (i.e. plants that live in the same habitats or share similar morphological characteristics), so it seems that the environment has no influence on the biosynthesis of the volatiles of these plants.