Enhanced CO2 separation properties by incorporating acid-functionalized graphene oxide into polyimide membrane

Graphene oxide (GO) was modified using isocyanate (MDI) and ethylenediaminetetraacetic acid (EDTA) for the fabrication of flat-sheet GO-MDI-EDTA composite. Subsequently, this composite was incorporated into the Matrimid® (PI) matrix to fabricate mixed matrix membranes (MMMs) for CO2 separation. The influence of GO-MDI-EDTA composite on the CO2 separation properties of PI was evaluated. Scanning electron microscopy showed that GO-MDI-EDTA enhanced the interface compatibility with the polymer matrix. MMMs showed significantly enhanced CO2 permeability compared with pure Matrimid® membrane. The improvement of CO2 separation performance can be attributed to the uniform dispersion of GO-MDI-EDTA sheets in the PI matrix. The carboxylic group contained in GO-MDI-EDTA has a good affinity with CO2, and the increased carboxyl sites can effectively transport CO2. The GO-MDI-EDTA lamellar structure increased the gas transmission path, which is not conducive to the passage of large dynamic diameter gases (CH4, N2), thereby improving the separation performance. The MMMs doped with GO-MDI-EDTA-0.5% showed optimal gas separation performance. The CO2 permeability is 12.85 Barrer, the CO2/N2 selectivity is 47.59, and the CO2/CH4 selectivity is 53.54.

Hg release and Hg nanoparticle formation upon flooding of an agriculturally used fluvisol.

<p>Soils in legacy sites of chlor-alkali and acetaldehyde production are point sources of mercury (Hg) to downstream eco-systems. Flooding and agricultural activities may influence the fate of Hg by altering redox conditions, microbial activity and carbon budgets. However, the complex interplay between these parameters is still not well understood. The aim of this work was to better understand the effect of flooding and fertilisation on the release/sequestration of Hg in a polluted  floodplain soil.</p><p>We conducted a flooding-draining incubation experiment on two Hg polluted fluvisols (2.4 ± 0.1 and 44.8 ± 0.5 mg.kg<sup>-1</sup> Hg). The soils originated from an agriculturally used floodplain situated in the Rhone Valley (Valais, Switzerland) and were exposed to Hg pollution by an acetaldehyde producing plant until the 1970’s. They were incubated in triplicates for each treatment. During 56 days the soils were alternately flooded and drained in intervals of 14 days. For flooding, we used an artificial rain water and a 1:1.5 soil:water ratio. The influence of agricultural activites was studied by adding 0.6% (w/w) of liquid manure in a separate treatment. We monitored pore water Hg<sub>total</sub>, Eh, pH, DOC and relevant metals in daily time intervals. Further, the sampled pore water was filtered in distinct intervals (10µm / 5µm / 0.45µm / 0.020µm) at specific time points and analyzed for Hg<sub>total</sub>. Additionally, the 0.45µm fraction was sampled to study the evolution of colloidal Hg with AF4-ICP-MS.</p><p>We observed differences between soil treated with or without manure. In the microcosms (MCs) treated with manure, we observed a Hg<sub>total</sub> release along with reductive disolution of Mn-oxides peaking (Hg<sub>total</sub>: 20.8 µg.L<sup>-1</sup>) after 5 days of flooding. Subsequently, pore water Hg<sub>total</sub> decreased with a simultanous decrease in pore water SO<sub>4</sub><sup>2-</sup>. This is likely due to the onset of sulfate reduction. Additionally, we observed the increase of inorganic colloidal Hg in the range of 10nm hydro dynamic diameter in manure treated MCs with higher contaminated soil during the first 2 and 10 days of incubation.</p><p>In the MCs without manure addition, the onset of reductive dissolution of Mn oxides was 2 days later. Pore water Hg<sub>total</sub>  peaked only after 7 days of flooding (19.76 µg.L<sup>-1 </sup>Hg) and remained at the same levels until the end of the first flooding period. This is likely due to a lower microbial activity and a lower labile carbon pool in the untreated compared to the treated soils.</p><p>Flooding of our polluted fluvisol releases Hg after few days. The additional manuring accelerates this process. However, it as well accelerates the subsequent decrease of Hg<sub>total</sub> in the pore water. This is among others due to the formation of Hg nanoparticles. We plan to use electron microscopy in order to draw conclusions about the nature of these Hg nanoparticles.</p>

Dynamic diameter response of intraparenchymal penetrating arteries during cortical spreading depression and elimination of vasoreactivity to hypercapnia in anesthetized mice

Cortical spreading depression (CSD) induces marked hyperemia with a transient decrease of regional cerebral blood flow (rCBF), followed by sustained oligemia. To further understand the microcirculatory mechanisms associated with CSD, we examined the temporal changes of diameter of intraparenchymal penetrating arteries during CSD. In urethane-anesthetized mice, the diameter of single penetrating arteries at three depths was measured using two-photon microscopy during passage of repeated CSD, with continuous recordings of direct current potential and rCBF. The first CSD elicited marked constriction superimposed on the upstrokes of profound dilation throughout each depth of the penetrating artery, and the vasoreaction temporally corresponded to the change of rCBF. Second or later CSD elicited marked dilation with little or no constriction phase throughout each depth, and the vasodilation also temporally corresponded to the increase of rCBF. Furthermore, the peak dilation showed good negative correlations with basal diameter and increase of rCBF. Vasodilation induced by 5% CO2 inhalation was significantly suppressed after CSD passage at any depth as well as hyperperfusion. These results may indicate that CSD-induced rCBF changes mainly reflect the diametric changes of the intraparenchymal arteries, despite the elimination of responsiveness to hypercapnia.

Dynamic Diameter Determination of Circular Brushes

After milling process burrs can form as a result of plastic deformation of the material. Wire brushing can be used as a fully automated method of deburring on machining centres. In order to provide the same effects after brush change it is important to precisely determine the tool diameter. The article presents the method of dynamic diameter determination of circular brushes, which is the diameter of the brush during rotation.

Experimental Investigation of 99mТс-Nanotech Used for Lymph Nodes Visualization

Measurement of colloidal particles size was performed on a NICOMP 380 ZLS. Pharmacokinetics. Radiometry of the organs was carried out on γ-spectrometer. Measurement of the sizes of radioactive particles of 99mTc-nanotech showed that average dynamic diameter of RFP particle ranged from 16.7 to 24.5 nm. 99mTc-nanotech received by the blood is actively trapped by liver and spleen. Inguinal lymph node in all animals was clearly visualized during lymphoscintigraphy on the 15th minute. Maximum accumulation of 99mTc-nanotech was observed in 3 hours. Experimental study of radiopharmaceutical 99mTc-nanotech showed that the nanocolloid can be used for lymphoscintigraphy and visualization of “sentinel” nodes.

Operational Mechanism of Square Capillary Looped Pulsating Heat Pipe

Pulsating Heat Pipe (PHP) has the turn structure of capillary and the mechanism is paid much more attention. The circulation of Looped Pulsating Heat Pipe (LPHP) is modelled to couple the heat transfers, volume flow rates, operational driving forces and flow resistances. The analysis and calculation show that, the square capillary LPHP can be optimized by adjusting the coupled dominating parameters to improve the flow and performance. The working fluid, the transferred power and the dynamic diameter will exert essential influences on the LPHP performance, the thermal resistance of the LPHP can be as small as 0.05°C/W.

Site index in agroforestry systems: age-dependent and age-independent dynamic diameter growth models forQuercus ilexin Iberian open oak woodlands

Despite Quercus ilex L. being one of the most widespread tree species in the Mediterranean basin, there are no growth models in the literature for this species. In this study, we compare age-dependent and age-independent dynamic diameter growth models and discuss the concept of dominance in open stands. A posteriori dominance was determined to fit potential age-dependent growth models and a site index based on diameter growth was defined. Formulations derived from power decline base models (Korf and Hossfeld) best described diameter growth. The best approach for age-dependent models was a polymorphic and with variable asymptotes generalized algebraic difference approach formulation. Residual errors in trees between 20 and 55 cm ranged from ~7.0% in potential growth models to ~15% in age-independent models expanded by density. Using a unique age-dependent dynamic equation for all trees, regardless of dominance, did not increase the error very much. In age-independent models, the inclusion of the defined site index reduced the prediction error but requires that the age of trees is estimated to determine the site index. The difficulty of estimating Q. ilex age makes age-independent models very attractive for system modelling. Age-independent models could be useful in other ecosystems where age estimation is problematic.