Recently, microfluidic stretchable electronics has attracted great interest from academia since conductive liquids allow for larger cross-sections when stretched and hence low resistance at longer ...lengths. However, as a serial process it has suffered from low throughput, and a parallel processing technology is needed for more complex systems and production at low costs. In this work, we demonstrate such a technology to implement microfluidic electronics by stencil printing of a liquid alloy onto a semi-cured polydimethylsiloxane (PDMS) substrate, assembly of rigid active components, encapsulation by pouring uncured PDMS on-top and subsequent curing. The printing showed resolution of 200 μm and linear resistance increase of the liquid conductors when elongated up to 60%. No significant change of resistance was shown for a circuit with one LED after 1000 times of cycling between a 0% and an elongation of 60% every 2 s. A radio frequency identity (RFID) tag was demonstrated using the developed technology, showing that good performance could be maintained well into the radio frequency (RF) range.
The chemical stability of the Li-O 2 battery components (cathode and electrolyte) in contact with lithiumperoxide (Li 2 O 2 ) was investigated using X-ray photoelectron spectroscopy (XPS). XPS is a ...versatile method to detect amorphous as well as crystalline decomposition products of both salts and solvents. Two strategies were employed. First, cathodes including carbon, α‑MnO 2 catalyst, and Kynar binder (PVdF-HFP) were exposed to Li 2 O 2 and LiClO 4 in propylenecarbonate (PC) or (tetraethylene glycol dimethyl ether) TEGDME electrolytes. The results indicated that Li 2 O 2 degrades TEGDME to carboxylate containing species and that the decomposition products in turn degraded the Kynar binder. The α‑MnO 2 catalyst was unaffected. Second, Li 2 O 2 model surfaces were kept in contact with different electrolytes to investigate the chemical stability, and also the resulting surface layer on Li 2 O 2 . Further, the XPS experiments revealed that the Li salts LiPF 6 , LiBF 4 , and LiClO 4 decomposed to form LiF or LiCl together with P-O or B-O bond containing compounds when exposed to Li 2 O 2 . PC decomposed to carbonate and ether based species. The degradation of the electrolytes increased from short to long exposure time indicating that the surface layer on Li 2 O 2 became thicker by increasing time. Overall, it was shown that a mixture of ethylene carbonate and diethyl carbonate (EC/DEC) is more robust in contact with Li 2 O 2 compared to PC.
It is demonstrated that it is possible to coat the individual fibers of wood-based nanocellulose with polypyrrole using in situ chemical polymerization to obtain an electrically conducting continuous ...high-surface-area composite. The experimental results indicate that the high surface area of the water dispersed material, to a large extent, is maintained upon normal drying without the use of any solvent exchange. Thus, the employed chemical polymerization of polypyrrole on the microfibrillated cellulose (MFC) nanofibers in the hydrogel gives rise to a composite, the structure of whichunlike that of uncoated MFC paperdoes not collapse upon drying. The dry composite has a surface area of ∼90 m2/g and a conductivity of ∼1.5 S/cm, is electrochemically active, and exhibits an ion-exchange capacity for chloride ions of 289 C/g corresponding to a specific capacity of 80 mAh/g. The straightforwardness of the fabrication of the present nanocellulose composites should significantly facilitate industrial manufacturing of highly porous, electroactive conductive paper materials for applications including ion-exchange and paper-based energy storage devices.
Overoxidised polypyrrole (PPy) paper has been employed as a mesoporous separator for lithium metal batteries (LMBs) based on its narrow pore size distribution, good thermal stability, high ionic ...conductivity (1.1 mS cm −1 with a LP40 electrolyte) and high electrolyte wettability. The overoxidised PPy paper was produced from a PPy/cellulose composite using a combined base and heat-treatment process, yielding a highly interrupted pyrrole molecular structure including N-containing polar groups maintaining the readily adaptable mesoporous structure of the pristine PPy paper. This well-defined pore structure gave rise to a homogeneous current distribution which significantly increased the performance of a LiFePO 4 |Li cell. With the overoxidised PPy separator, a symmetric Li|Li cell could be cycled reversibly for more than 600 h without any short-circuits in a LP40 electrolyte. This approach facilitates the manufacturing of well-defined separators for fundamental investigations of the influence of the separator structure on the performance of LMBs.
α-Synuclein (α-Syn) is an intrinsically disordered protein which self-assembles into highly organized β-sheet structures that accumulate in plaques in brains of Parkinsonâs disease patients. ...Oxidative stress influences α-Syn structure and self-assembly; however, the basis for this remains unclear. Here we characterize the chemical and physical effects of mild oxidation on monomeric α-Syn and its aggregation. Using a combination of biophysical methods, small-angle X-ray scattering, and native ion mobility mass spectrometry, we find that oxidation leads to formation of intramolecular dityrosine cross-linkages and a compaction of the α-Syn monomer by a factor of â2. Oxidation-induced compaction is shown to inhibit ordered self-assembly and amyloid formation by steric hindrance, suggesting an important role of mild oxidation in preventing amyloid formation.
The primary objective of the present study was to evaluate the concentrations and short and long-term excess mortality attributed to PM2.5, NO2, and O3 observed in ambient air of Ahvaz during March ...2014 to March 2017 period using the AirQ + software developed by the World Health Organization (WHO), which is updated in 2016 by WHO European Centre for Environment and Health. The hourly concentrations of PM2.5, O3, and NO2 measured at different regulatory monitoring network stations in Ahvaz city were obtained from the Department of Environment (DOE) of the city. Then, for various air quality monitoring stations, the 24-h average concentration of PM2.5, 1-h average of NO2 concentration, and maximum daily 8-h O3 concentrations were calculated using Excel 2010 software. When the maximum daily 8-h ozone means exceeding the value of 35, it was subtracted from 35 to calculate SOMO35 indicator for modeling. Validation of air quality data was performed according to the Aphekom and WHO's methodologies for health impact assessment of air pollution. Year-specific city population and baseline incidence of the health outcomes were obtained. The three-year averages of PM2.5, NO2, and O3 concentrations were 68.95 (±39.86) μg/m3, 135.90 (±47.82) μg/m3, and 38.63 (±12.83) parts-per-billion-volume (ppbv), respectively. SOMO35 values of ozone were 6596.66, 3411.78, and 470.88 ppbv in 2014–2015, 2015–2016, and 2016-2017 years, respectively. The AP and number of natural deaths due to NO2 were higher than PM2.5 except the last year (2016–2017), causing about 39.18%, 40.73%, and 14.39% of deaths within the first, the second, and the third year, respectively. However, for the last year, the natural mortality for PM2.5 was higher than NO2 (34.46% versus 14.39%). The total number of natural mortality caused by PM2.5 and NO2 in all years was 4061 and 4391, respectively. A significant number of deaths was estimated to be attributed to the given air pollutants. It can be concluded that by designing and implementing air pollution control strategies and actions, both health effects and economic losses will be prevented.
•Attributed short and long term morbidity for PM2.5, NO2 and O3 was assessed.•Year-specific city population and baseline incidence of the health outcomes were obtained.•Number of death cases for IHD, COPD, lung cancer, and ALRI attributed to PM2.5 was estimated.•The attributable health effects of ozone were low and negligible.
A superconductor is a material that can conduct electricity without resistance below a superconducting transition temperature, Tc. The highest Tc that has been achieved to date is in the copper oxide ...system: 133 kelvin at ambient pressure and 164 kelvin at high pressures. As the nature of superconductivity in these materials is still not fully understood (they are not conventional superconductors), the prospects for achieving still higher transition temperatures by this route are not clear. In contrast, the Bardeen-Cooper-Schrieffer theory of conventional superconductivity gives a guide for achieving high Tc with no theoretical upper bound--all that is needed is a favourable combination of high-frequency phonons, strong electron-phonon coupling, and a high density of states. These conditions can in principle be fulfilled for metallic hydrogen and covalent compounds dominated by hydrogen, as hydrogen atoms provide the necessary high-frequency phonon modes as well as the strong electron-phonon coupling. Numerous calculations support this idea and have predicted transition temperatures in the range 50-235 kelvin for many hydrides, but only a moderate Tc of 17 kelvin has been observed experimentally. Here we investigate sulfur hydride, where a Tc of 80 kelvin has been predicted. We find that this system transforms to a metal at a pressure of approximately 90 gigapascals. On cooling, we see signatures of superconductivity: a sharp drop of the resistivity to zero and a decrease of the transition temperature with magnetic field, with magnetic susceptibility measurements confirming a Tc of 203 kelvin. Moreover, a pronounced isotope shift of Tc in sulfur deuteride is suggestive of an electron-phonon mechanism of superconductivity that is consistent with the Bardeen-Cooper-Schrieffer scenario. We argue that the phase responsible for high-Tc superconductivity in this system is likely to be H3S, formed from H2S by decomposition under pressure. These findings raise hope for the prospects for achieving room-temperature superconductivity in other hydrogen-based materials.
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Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
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► Usage of TiO2/AC for the treatment of the wastewater containing dyes and pigments. ► Adjusting experimental conditions for MO removal using TiO2/AC. ► Usage of solar energy as ...well as visible light in MO degradation. ► Reuse of TiO2/activated carbon after dye removal. ► Reuse of wastewater containing azo dyes in agriculture purposes.
The activated carbon loaded TiO2 photocatalyst was prepared and characterized by FT-IR, scanning electron micrograph (SEM) and X-ray diffraction (XRD). The photocatalytic efficiency of activated carbon loaded TiO2 was evaluated by photocatalytic oxidation of Methyl Orange (MO) dye in aqueous medium using visible and solar light. TiO2/AC exhibited higher photocatalytic oxidation efficiency of MO than that of naked TiO2. The various experimental parameters like initial dye concentration, amount of catalyst and solution pH for efficient dye degradation are investigated. Activity measurements performed under visible light and solar irradiation have shown good results for the photo degradation of MO in aqueous solution. The higher efficiency of TiO2/AC is due to synergy effect of activated carbon. Addition of high adsorption capacity activated carbon to photoactive titanium dioxide in photocatalytic degradation of dyes improves the efficiency of dye mineralization. The present catalysts show high adsorptivity and high photoactivity for the degradation of the MO dye and can be very easily separated from the solution by sedimentation or simple filtration and it can be used repeatedly for MO removal with preservation of its photoactivity.
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