High Ionic Conductivity Motivated by Multiple Ion-Transport Channels in 2D MOF-Based Lithium Solid State Battery

Metal-organic frameworks (MOFs) have been proposed as novel fillers for constructing polymer solid electrolytes based composite electrolytes. However, MOFs are generally used as passive fillers, in-depth revealing the binding mode between MOFs and polyethylene oxide (PEO), the critical role of MOFs in facilitating Li⁺ transport in solid electrolytes is full of challenges. Herein, inspired by density functional theory (DFT) the 2D-MOF with rich unsaturated metal coordination sites that can bind the O atom in PEO through the metal–oxygen bond,  anchor TFSI⁻ to release Li⁺, resulting in a remarkable Li⁺ transference number of 0.58, is reported according well with the experimental results and molecular dynamics (MD) simulation. Impressively, after the introduction of the 2D-MOF, the Li⁺ can rapidly hop along the benzene ring center within the 2D-MOF plane, and the interface between the benzene ring and PEO can also serve as a fast Li⁺ migration pathway, delivering multiple ion-transport channels, which present a high ion conductivity of 4.6 × 10⁻⁵ S cm⁻¹ (25 °C). The lithium symmetric battery is stable for 1300 h at 60 °C, 0.1 mA cm⁻². The assembled lithium metal solid state battery maintains high capacity of 162.8 mAh g⁻¹ after 500 cycles at 60 °C and 0.5 C. This multiple ion-transport channels approach brings new ideas for designing advanced solid electrolytes.     

Oxidative polymerization of 3,4-ethylenedioxythiophene using transition-metal tetrasulfonated phthalocyanine

A method for the synthesis of water-soluble polyethylenedioxythiophene (PEDOT) by using transition-metal tetrasulfonated phthalocyanine (TSPc) and hydrogen peroxide as effective catalysts in the presence of sulfonated polystyrene (SPS) is reported. The reactions were carried out with different catalysts, such as iron, cobalt and manganese phthalocyanine. Metallophthalocyanines have shown good activities for polymerization, although they degraded easily under oxidizing conditions. In order to determine the role of pH during the polymerization, the reaction was carried out under different pH conditions 2, 2.5 and 3 and the best results were obtained at pH 2. The conductivity of our product was obtained and compared with similar commercial material. PEDOT was characterized by UV–vis and FT-IR spectroscopies and also cyclic voltammetry. Cyclic voltammetry (CV) demonstrated that the synthesized polymer has convenient electroactivity.     

Evaluation of Composition-Dependent Collection Efficiencies for the Aerodyne Aerosol Mass Spectrometer using Field Data

In recent years, Aerodyne aerosol mass spectrometers (AMS) have been used in many locations around the world to study the size-resolved, nonrefractory chemical composition of ambient particles. In order to obtain quantitative data, the mass or (number) of particles detected by the AMS relative to the mass (or number) of particles sampled by the AMS, i.e., the AMS collection efficiency (CE) must be known. Previous studies have proposed and used parameterizations of the AMS CE based on the aerosol composition and sampling line relative humidity. Here, we evaluate these parameterizations by comparing AMS mass concentrations with independent measurements of fine particle volume or particle-into-liquid sampler (PILS) ion chromatography measurements for 3 field campaigns with different dominant aerosol mixtures: (1) acidic sulfate particles, (2) aerosol containing a high mass fraction of ammonium nitrate, and (3) aerosol composed of primarily biomass burning emissions. The use of the default CE of 0.5 for all campaigns resulted in 81–90% of the AMS speciated and total mass concentrations comparing well with fine particle volume or PILS measurements within experimental uncertainties, with positive biases compared with a random error curve. By using composition-dependent CE values (sometimes as a function of size) which increased the CE for the above aerosol types, the fraction of data points within the measurement uncertainties increased to more than 92% and the mass concentrations decreased by ～5–15% on an average. The CE did not appear to be significantly dependent on changes in organic mass fraction although it was substantial in the 3 campaigns (47, 30, and 55%).

Copyright 2012 American Association for Aerosol Research     

In-Situ Reduction of Promoted Cobalt Oxide Supported on Alumina by Environmental Transmission Electron Microscopy

Abstract  

Reduction of 12wt.%Co/0.5wt.%Re/α-Al₂O₃ Fischer–Tropsch catalyst has been studied in-situ in an environmental transmission electron microscope. Reduction of Co₃O₄ to metallic cobalt was observed dynamically at 360 °C under 3.4 mbar H₂. Structural and morphological changes were observed by high resolution transmission electron microscopy and scanning transmission electron microscopy imaging. The cobalt particles were mainly face centred cubic while some hexagonal close packed particles were also found. Reoxidation of the sample upon cooling to room temperature, still under flowing H₂, underlines the reactivity of the nanoparticles and the importance of controlling the gas composition and specimen temperature during this type of experiment. Similar behaviour was observed for a non-promoted catalyst. Imaging and analysis of the promoted sample before and after reduction indicated a uniform distribution of the promoter.     

Electrochemical oxidation of 4-morpholinoaniline in aqueous solutions: Synthesis of a new trimer of 4-morpholinoaniline

Electrochemical oxidation of 4-morpholinoaniline has been studied in various pHs using cyclic voltammetry and controlled-potential coulometry. The electrochemical trimerization of 4-morpholinoaniline is described and its mechanism has been studied in aqueous solution. This method provides a green, reagent-less, and environmentally friendly procedure with high atom economy, for the synthesis of “4-morpholinoaniline-trimer” using a carbon electrode in an undivided cell in good yield and purity.     

The Effect of an Energy Restricted Low Glycemic Index Diet on Blood Lipids, Apolipoproteins and Lipoprotein (a) Among Adolescent Girls with Excess Weight: a Randomized Clinical Trial

Some studies focused on the effect of the dietary glycemic index on lipoproteins and apolipoproteins in adults; however, little evidence exists among adolescents regarding the effect of a low glycemic index (LGI) diet on apolipoproteins and lipoprotein (a) (Lpa). This study was conducted to evaluate the effect of an LGI diet on the lipid profile, apolipoproteins and Lpa among overweight and obese adolescent girls. For this parallel designed randomized clinical trial, 50 healthy overweight/obese girls at pubertal ages were randomly allocated to an LGI or a healthy nutritional recommendations (HNR) based diet. Equal macronutrient distributed diets were prescribed to both groups. Biochemical measurements included lipid profile, apolipoprotein A, apolipoprotein B and Lpa were conducted before and after 10 weeks of intervention. Forty one adolescent girls completed the study. The dietary glycemic index in the LGI group was 42.67 ± 0.067. There were no differences in the mean of blood lipid indices baseline and after intervention between two groups. There were no significant differences between the two groups regarding lipid profiles, apolipoproteins and Lpa. There were no significant differences in lipid profiles, apolipoproteins and Lpa between the LGI diet and the HNR-based diet and the impact of these two diets on lipid profile was equal in this trial. Trial registry code: IRCT201109272839N4.     

Characteristics of secondhand electronic cigarette aerosols from active human use

The electronic cigarette (EC) is a new source of indoor airborne particles. To better understand the impacts of secondhand vaping (SHV) emissions on indoor air quality, real-time measurements of particle size distribution, particle number concentration (PNC), fine particulate matter (PM_2.5), CO₂, CO, and formaldehyde were conducted before, during, and after 10 min EC-use among 13 experienced users in an 80 m³ room. To assess particle transport in the room, multiple sampling locations were set up at 0.8, 1.5, 2.0, and 2.5 m away from the subjects. The arithmetic mean (standard deviation) of background PNC and PM_2.5 concentrations in the room were 6.39 × 10³ (1.58 × 10²) particles/cm³ and 8 (1) μg/m³, respectively. At 0.8 m away from EC users, right after initiation of puffing, the PNC and PM_2.5 concentrations can reach a peak of ～10⁵ particles/cm³ and ～3 × 10³ µg/m³, respectively, and then dropped quickly to background levels within 20 s due to dilution and evaporation. At the 0.8 m sampling location, the mean PNC and PM_2.5 concentrations during puffing were 2.48 × 10⁴ (2.14 × 10⁴) particles/cm³ and 188 (433) µg/m³, respectively. In addition, two modes of SHV particles were observed at about 15 and 85 nm. Moreover, concentrations of SHV particles were negatively correlated with the distances to EC users. At the 1.5 m location, PNC and PM_2.5 levels were 9.91 × 10³ (1.76 × 10³) particles/cm³ and 19 (14) µg/m³, respectively. Large variations of mean PNC levels exhaled per puff were observed both within and between EC users. Data presented in this study can be used for SHV particle exposure assessment.

Copyright © 2017 American Association for Aerosol Research     

ICT and environmental sustainability: A global perspective

The positive and negative environmental impacts of information and communication technologies (ICTs) are widely debated. In theory, ICT is among the sources contributing to the increasing levels of CO₂ emissions in terms of production of ICT machinery and devices, energy consumption, and recycling of electronic waste. However, ICT is also expected to reduce CO₂ emissions on a global scale by developing smarter cities, transportation systems, electrical grids, industrial processes, and energy saving gains. These two effects work in opposite direction, creating an inverted-U relationship between ICT and CO₂ emissions. The aim of this study is to investigate this non-linear relationship between ICT and CO₂ emissions on a global scale. Given that global warming is a global issue, it is necessary to look at this relationship in countries at all levels of development. To this end, we use a panel data set consisting of 142 economies, split into 116 developing and 26 developed countries, over the period 1995–2010. The results of our empirical study confirm that the relationship between ICT and CO₂ emissions is an inverted U-shaped relationship. Moreover, while for the sample of developing countries, the ICT turning point is well above the mean value, the opposite is true for the sample of developed countries. This implies that many developed countries have already attained the level of ICT development, at which CO₂ emissions decreases as the level of ICT development improves further.