159,701 research outputs found
Assessing the interaction of an energy tunnel with the underground thermal conditions in an urban area
No full textIn the very shallow depths of urban areas it is difficult to find natural undisturbed underground thermal conditions because of anthropic interventions. Moreover, these areas are being increasingly used for energy purposes, for example implementing the technology of shallow geothermal systems to provide clean thermal energy and supply the thermal demand of buildings in both winter and summer seasons. The heat exchanged by these types of renewable energy technologies, in particular ground source heat pump systems such as open loop and closed loop ones, in combination with further anthropogenic activities, results in altered thermal regimes in the subsurface. Energy tunnels, which are achieved by thermally activating the tunnel lining, have recently gained attention among closed loop geothermal systems. Therefore, when planning an urban energy tunnel, attention has to be devoted to the initial underground thermal conditions and to the interactions the pre-existing thermal regime will have with the energy tunnel itself. To this aim, the paper outlines a methodological approach which is then applied to a case study in Turin, Italy, where a new metro line is planned. Thermo-hydraulic numerical modelling is adopted to reproduce the thermally disturbed subsurface environment in the study area prior to the energy tunnel’s thermal activation, due to the presence of multiple heat sources (open loop and closed loop systems, underground buildings, car parks and infrastructures), as well as after its commissioning. Results are illustrated in terms of temperature maps and cross sections where the thermally affected zones due to open loop, mainly, and closed loop systems are depicted depending on the operational mode of the shallow geothermal systems. Those results highlight that, when the installation of a new energy tunnel is envisaged, it is necessary to consider the current geothermal exploitation of the area and the operation of neighbouring similar systems
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Maintenance of broad-host range plasmids and engineered <i>S</i>. <i>alvi</i> over time.
No full textEach broad-host-range vector has a distinct level of maintenance in S. alvi cells, as demonstrated in vitro (a) and in vivo (c). Box plots represent plasmid maintenance median values of n biological replicates. Plasmid maintenance was estimated by measuring the percentage of fluorescent colony forming units (CFUs) plated onto nonselective media of samples obtained from (a) liquid cultures (in vitro) after 3 days of growth with (+Ab) or without (−Ab) spectinomycin supplementation; or (c) from feces (in vivo) collected 7 (orange) and 14 (red) days after gut monocolonization of bees continuously fed sugar water supplemented with (+Ab) or without (−Ab) spectinomycin. Only samples for which we detected bacterial colonies upon plating the fecal material were considered. (b) Schematic outline of the in vivo experiment to estimate engineered S. alvi colonization maintenance. Arrows indicate the 2 times of feces sampling. (d) Bacterial load of engineered S. alvi cells found in feces collected 7 (orange) and 14 (red) days after gut monocolonization of bees continuously fed sugar water supplemented with (+Ab) or without (−Ab) spectinomycin. Concentrations of our different S. alvi strains isolated from the feces of bees co-colonized with the natural gut community and that were fed sugar water without spectinomycin (+Gc) was also analyzed. Those CFUs values were obtained by plating diluted feces onto selective media (i.e., supplemented with spectinomycin). Bees for which we did not detect engineered bacteria were considered noncolonized individuals. The rate of colonized bees (r) and the number of bees sampled (n) are provided. Corresponding median values of colonized bees only are represented by colored horizontal bars with interquartile ranges. Plasmids used for all panels in S. alvi were pAC10, pAC04, pBTK570, and pAC11, carrying the pVS1, pBBR1, RSF1010, and pTF-FC2 origins of replication, respectively. The data underlying this Figure can be found in the S1 Data file, sheets “Fig 4A,” “Fig 4C,” and “Fig 4D”.</p
Effect of hydrophobic butyl group on the physicochemical properties of anion exchange membranes based on pyperazinum functionalized polyketone copolymer
No full textIn this report, anion exchange membranes based on poly[(N-(1,4-dimethyl piperaziniumethyl)-ethylenepyrrole)(X)/ethyleneketone/propyleneketone/N-(n-butyl)ethylenepyrrole], where X = I− or OH−, terpolymer are prepared by converting the 1,4-diketonic groups of an aliphatic poly[ethylene ketone/propylene ketone] (PKK) into pyrrole substituted repeat units through a Paal-Knorr reaction. These materials are prepared by co-reacting 1-(2-aminoethylpiperazine) and n-butylamine in different amines/PKK molar ratios to investigate the effect of varying degree of functionalization (f) and the incorporation of hydrophobic butyl pendant groups on the physicochemical properties of the membranes. The molecular structure and composition of the membranes are confirmed by ATR-FTIR and CHNS/O elemental analysis, while their electrochemical and physical properties are characterized through evaluation of water uptake (WU %), ion exchange capacity (IEC), thermal stability, ionic conductivity, and alkaline stability. BES studies reveal ionic conductivity values of 0.49 and 0.87 mS cm−1 at 50 °C for the membranes in iodide and hydroxide form, respectively. The membrane PB-FPKK0.47/0.04(OH)0.43 demonstrates an exceptional chemical stability for 720 hours at 45 °C in 1 M KOH aqueous solution
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Functional classification of the accessory genes of (A) S. <i>alvi</i> SAGs and (B) <i>G. apicola</i> SAGs based on COG categories.
No full text<p>303 of 755 accessory genes of <i>S. alvi</i> SAGs and 476 of 851 accessory genes of <i>G. apicola</i> SAGs could be classified into COGs. Categories covering ≥5% of the classified accessory genes are shown. Minor categories (<5%) are summarized in the grey colored area of the pie charts. Categories R, S, and L include genes associated with mobile genetic elements.</p
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