Options for processing of aspen wood to carbon materials

Thermochemical processing of aspen wood to produce carbon materials is of interest considering that it allows increasing the cost of its products several times and enhancing the sustainability of forest complex enterprises.Currently, the enterprises are confined to the manufacture of charcoal, although it is possible to produce other carbon materials, such as charcoal briquettes, activated carbon and oxidized coal.While processing aspen wood, it is feasible to arrange manufacturing charcoal briquettes. Increased mechanical strength and high bulk density of briquettes raises the range of economically viable transportation of manufactured products, i.e. logistics is being improved.To obtain stable quality activated carbon from aspen coal, water vapor activation is the least environmentally hazardous. For such activation implementation, we recommend using a rotary kiln equipped with a Z-shaped insert. For reasons of environmental safety, the oxidation of activated carbon is preferably carried out using hot, humid air. In this case, unlike liquid-phase oxidation, no wastewater is formed. © 2019 IOP Publishing Ltd. All rights reserved

The effect of multiple paternity on genetic diversity during and after colonisation

In metapopulations, genetic variation of local populations is influenced by the genetic content of the founders, and of migrants following establishment. We analyse the effect of multiple paternity on genetic diversity using a model in which the highly promiscuous marine snail Littorina saxatilis expands from a mainland to colonise initially empty islands of an archipelago. Migrant females carry a large number of eggs fertilised by 1 - 10 mates. We quantify the genetic diversity of the population in terms of its heterozygosity: initially during the transient colonisation process, and at long times when the population has reached an equilibrium state with migration. During colonisation, multiple paternity increases the heterozygosity by 10 - 300 % in comparison with the case of single paternity. The equilibrium state, by contrast, is less strongly affected: multiple paternity gives rise to 10 - 50 % higher heterozygosity compared with single paternity. Further we find that far from the mainland, new mutations spreading from the mainland cause bursts of high genetic diversity separated by long periods of low diversity. This effect is boosted by multiple paternity. We conclude that multiple paternity facilitates colonisation and maintenance of small populations, whether or not this is the main cause for the evolution of extreme promiscuity in Littorina saxatilis.Comment: 7 pages, 5 figures, electronic supplementary materia

The adaptation of academics to the Covid-19 crisis in terms of work time allocation

Academics have seen their work environment and routines severely affected by the Covid19 pandemic. This topic has been analyzed by the literature, mostly from personal and descriptive perspectives, that highlight the challenging transitions and adaptations that academics have endured concerning their work and life-balance. This research complements those studies, by using a sample of university academics working all around the world in all disciplinary fields and focuses on a longitudinal perspective of workload and task time allocation of academic work. The findings show that academics which in general had long working hours, further increased their time of the week dedicated to work leading possibly to the reported cases in the literature of increasing stress and burnout during the pandemic. These effects were found to be similar to all academics, independently of their gender and disciplinary field. More concerning is that this increased number of hours worked per week appears to have established itself as part of the new normal. The main driver for the increased workload is associated with teaching, and to a lesser extent with administrative duties.info:eu-repo/semantics/publishedVersio

Targeted re-sequencing reveals geographic patterns of differentiation for loci implicated in parallel evolution

Parallel divergence and speciation provide evidence for the role of divergent selection in generating biological diversity. Recent studies indicate that parallel phenotypic divergence may not have the same genetic basis in different geographical locations - "outlier loci" (loci potentially affected by divergent selection) are often not shared among parallel instances of phenotypic divergence. However, limited sharing may be due, in part, to technical issues if false positive outliers occur. Here, we test this idea in the marine snail Littorina saxatilis, which has evolved two partly isolated ecotypes (adapted to crab predation vs. wave action) in multiple locations independently. We argue that if the low extent of sharing observed in earlier studies in this system is due to sampling effects, we expect outliers not to show elevated FST when sequenced in new samples from the original locations, and also not to follow predictable geographical patterns of elevated FST . Following a hierarchical sampling design (within vs. between country), we applied capture sequencing, targeting outliers from earlier studies and control loci. We found that outliers again showed elevated levels of FST in their original location, suggesting they were not generated by sampling effects. Outliers were also likely to show increased FST in geographically close locations, which may be explained by higher levels of gene flow or shared ancestral genetic variation compared to more distant locations. However, in contrast to earlier findings, we also found some outlier types to show elevated FST in geographically distant locations. We discuss possible explanations for this unexpected result. This article is protected by copyright. All rights reserved

Shear viscosity in microscopic calculations of A+A collisions at energies of Nuclotron-based Ion Collider fAcility (NICA)

Time evolution of shear viscosity $\eta$, entropy density $s$, and their ratio $\eta / s$ in the central area of central gold-gold collisions at NICA energy range is studied within the UrQMD transport model. The extracted values of energy density, net baryon density and net strangeness density are used as input to (i) statistical model of ideal hadron gas to define temperature, baryo-chemical potential and strangeness chemical potential, and to (ii) UrQMD box with periodic boundary conditions to study the relaxation process of highly excited matter. During the relaxation stage, the shear viscosity is determined in the framework of Green-Kubo approach. The procedure is performed for each of 20 time slices, corresponding to conditions in the central area of the fireball at times from 1~fm/$c$ to 20~fm/$c$. For all tested energies the ratio $\eta / s$ reaches minimum, $\left( \eta/s \right)_{min} \approx 0.3$ at $t \approx 5$~fm/$c$. Then it increases up to the late stages of the system evolution. This rise is accompanied by the drop of both, temperature and strangeness chemical potential, and increase of baryo-chemical potential.Comment: LATEX, 9 pages, 10 figure

Phylogeographic history of flat periwinkles, Littorina fabalis and L. obtusata

Background The flat periwinkles, Littorina fabalis and L. obtusata, are two sister species widely distributed throughout the Northern Atlantic shores with high potential to inform us about the process of ecological speciation in the intertidal. However, whether gene flow has occurred during their divergence is still a matter of debate. A comprehensive assessment of the genetic diversity of these species is also lacking and their main glacial refugia and dispersal barriers remain largely unknown. In order to fill these gaps, we sequenced two mitochondrial genes and two nuclear fragments to perform a phylogeographic analysis of flat periwinkles across their distribution range. Results We identified two main clades largely composed by species-specific haplotypes corresponding to L. obtusata and L. fabalis, with moderate to strong support, respectively. Importantly, a model of divergence with gene flow between the two species (from L. obtusata to L. fabalis) was better supported, both in Iberia and in northern-central Europe. Three mitochondrial clades were detected within L. fabalis and two within L. obtusata, with strong divergence between Iberia and the remaining populations. The largest component of the genetic variance within each species was explained by differences between geographic regions associated with these clades. Our data suggests that overall intraspecific genetic diversity is similar between the two flat periwinkle species and that populations from Iberia tend to be less diverse than populations from northern-central Europe. Conclusions The phylogeographic analysis of this sister-species pair supports divergence with gene flow. This system thus provides us with the opportunity to study the contribution of gene flow and natural selection during diversification. The distribution of the different clades suggests the existence of glacial refugia in Iberia and northern-central Europe for both species, with a main phylogeographic break between these regions. Although the genetic diversity results are not fully conclusive, the lower diversity observed in Iberia could reflect marginal conditions at the southern limit of their distribution range during the current interglacial period

MIGRATION FORMS OF CHEMICAL ELEMENTS IN THE INTRUSIVE ROCKS OF THE EASTERN DESERT (EL SELA AREA, EGYPT)

In the Egypt's Eastern Desert intrusive rocks with U-REE mineralization (two-mica granites, microgranites, dolerites, and bostonites) are developed. We estimated the content of chemical elements in reference samples of intrusive rocks and also in their water-soluble (colloid-salt) fraction. This fraction is water-extracted from the rock under certain conditions. The rock sample and its colloid-salt fraction are analyzed using ICP-MS. The chemical characteristic of the extracted fraction reflects the mobile migrating part of the chemical elements in the composition of the rocks. Comparison of the obtained data allows us to estimate the share of migrating and weakly migrating elements

Nanoscale mosaicity revealed in peptide microcrystals by scanning electron nanodiffraction.

Changes in lattice structure across sub-regions of protein crystals are challenging to assess when relying on whole crystal measurements. Because of this difficulty, macromolecular structure determination from protein micro and nanocrystals requires assumptions of bulk crystallinity and domain block substructure. Here we map lattice structure across micron size areas of cryogenically preserved three-dimensional peptide crystals using a nano-focused electron beam. This approach produces diffraction from as few as 1500 molecules in a crystal, is sensitive to crystal thickness and three-dimensional lattice orientation. Real-space maps reconstructed from unsupervised classification of diffraction patterns across a crystal reveal regions of crystal order/disorder and three-dimensional lattice tilts on the sub-100nm scale. The nanoscale lattice reorientation observed in the micron-sized peptide crystal lattices studied here provides a direct view of their plasticity. Knowledge of these features facilitates an improved understanding of peptide assemblies that could aid in the determination of structures from nano- and microcrystals by single or serial crystal electron diffraction