Predicting the Distributions of Oxygen Species from Primary Devolatilization of Coals

Starting from an extension to FLASHCHAIN, this study interprets the evolution of coal oxygen during primary devolatilization. CO2 and H2O are primarily formed via bridge charring that accompanies depolymerization. At slower rates, CO plus additional CO2 and H2O are expelled from side chains without disintegrating coal macromolecules. Coal-O shuttled by tar is tracked as in FLASHCHAIN. New stoichiometry specifies the partitioning of O among the precursors to CO, CO2, and H2O. CO precursors incorporate about one-third of coal-O, regardless of coal rank. In contrast, the split of coal-O between CO2 and H2O precursors exhibits an erratic relation with coal quality, which has been resolved by a graphical method that connects precursor elimination during coalification to the displacements on the Van Krevelen diagram. With the roles for tar shuttling and macromolecular configuration accounted for, the model accurately interprets a database of 40 coals from all ranks with the new stoichiometry. The proportions of CO, CO2, and H2O are faithfully simulated across the entire rank spectrum, even when the observed CO2 levels scatter by a factor of 6 among high-volatile bituminous coals very similar in carbon content. Predictions are accurate throughout devolatilization except for the latest stage of CO evolution, and within the discrepancies among independent measurements for pressures from vacuum to 7.0 MPa, pending new data to characterize the final stage of CO formation and evaluate the predicted heating rate effect

Depolymerization Model for Coal Devolatilization: Bridges and Side Chains as the Reaction Centers

A phenomenological extension is developed for coal devolatilization, based on FLASHCHAIN’s mechanism for tar and lumped noncondensables. It segregates the reaction center population further into bridges and side chains with dissimilar reactivities that vary with rank. At low and medium temperatures, most bridges dissociate to produce tar precursors and noncondensables, whereas only a minor portion of side chains decomposes into gases; a fraction of both types of reaction centers may also be shuttled away as an element in tar molecules. When devolatilization continues to sufficiently high temperatures, bridges are depleted and side chain decomposition takes over to dominate gas formation. In the evaluations against atmospheric reaction dynamics of 16 coals from lignite to anthracite, the extension predicts with accuracy the disparate time scales for the evolution of tar and noncondensables, as well as the rank-dependent devolatilization rates. Also, except for the earlier evolution history at low heating rates, the extension demonstrates extrapolations within experimental uncertainty over a broad domain of operating conditions (heating rates from 1 to 10⁴ K/s and pressures from vacuum to 9 MPa) for coals across the entire rank spectrum

Depolymerization Model for Coal Devolatilization: Bridges and Side Chains as the Reaction Centers

A phenomenological extension is developed for coal devolatilization, based on FLASHCHAIN’s mechanism for tar and lumped noncondensables. It segregates the reaction center population further into bridges and side chains with dissimilar reactivities that vary with rank. At low and medium temperatures, most bridges dissociate to produce tar precursors and noncondensables, whereas only a minor portion of side chains decomposes into gases; a fraction of both types of reaction centers may also be shuttled away as an element in tar molecules. When devolatilization continues to sufficiently high temperatures, bridges are depleted and side chain decomposition takes over to dominate gas formation. In the evaluations against atmospheric reaction dynamics of 16 coals from lignite to anthracite, the extension predicts with accuracy the disparate time scales for the evolution of tar and noncondensables, as well as the rank-dependent devolatilization rates. Also, except for the earlier evolution history at low heating rates, the extension demonstrates extrapolations within experimental uncertainty over a broad domain of operating conditions (heating rates from 1 to 10⁴ K/s and pressures from vacuum to 9 MPa) for coals across the entire rank spectrum

Association between Fine Particulate Air Pollution and the Onset of Uveitis in Mainland China

Although it has long been recognized that air pollution can affect the immune system and human ocular symptoms, it is uncertain whether air pollutants may also contribute to the development of uveitis. This study aimed to quantify the association of particulate matters less than 2.5 μm (PM2.5) with uveitis onset. We combined monthly averages of PM2.5 concentrations, with data from the largest database of uveitis cases to assess the association between PM2.5 and uveitis onset. We further estimated the uveitis burden that was attributed to PM2.5 exposure and used choropleth maps to precisely characterize geographical variations. We found that a 10 μg/m3 increase in PM2.5 concentration was associated with a one-case per 10 individuals increase in uveitis onset across the dataset. Our results further suggest that PM2.5 concentrations above the level of the minimum exposure are responsible for 13% of novel uveitis cases in our cohort. Conclusion: These findings provide evidence supporting the association between fine particulate air pollution and uveitis onset.</p

Data for: A Cooperative Target Search Method Based on Intelligent Water Drops Algorithm

Simulation experiments results (search efficiency, region coverage rate, environment uncertainty reduction and the probability of collision of the proposed method, search methods based on the random search, greedy search, particle swarm optimization algorithm, ant colony algorithm, Q learning, conventional IWD algorithm, and the IWD algorithm with co-evolutionary strategy)

Novel Photoalignment Method Based on Low-Molecular-Weight Azobenzene Dyes and Its Application for High-Dichroic-Ratio Polarizers

Photoalignment is a simple technique for the manipulation of molecular orientations, which has been widely used in liquid crystal displays. Here, we propose a novel photoalignment method, in which an azobenzene dye thin film is deposited by thermal evaporation and in situ exposed to linearly polarized light simultaneously. We obtain polarizers with a dichroic ratio of up to 62, which is the highest value ever realized by a photoalignment method. Moreover, the polarizing thin film has a thickness of just 200 nm, compatible with flexible substrates, making it perfect for use as a dichroic polarizer in ultrathin and flexible displays

Novel Photoalignment Method Based on Low-Molecular-Weight Azobenzene Dyes and Its Application for High-Dichroic-Ratio Polarizers

Photoalignment is a simple technique for the manipulation of molecular orientations, which has been widely used in liquid crystal displays. Here, we propose a novel photoalignment method, in which an azobenzene dye thin film is deposited by thermal evaporation and in situ exposed to linearly polarized light simultaneously. We obtain polarizers with a dichroic ratio of up to 62, which is the highest value ever realized by a photoalignment method. Moreover, the polarizing thin film has a thickness of just 200 nm, compatible with flexible substrates, making it perfect for use as a dichroic polarizer in ultrathin and flexible displays

Novel Photoalignment Method Based on Low-Molecular-Weight Azobenzene Dyes and Its Application for High-Dichroic-Ratio Polarizers

Photoalignment is a simple technique for the manipulation of molecular orientations, which has been widely used in liquid crystal displays. Here, we propose a novel photoalignment method, in which an azobenzene dye thin film is deposited by thermal evaporation and in situ exposed to linearly polarized light simultaneously. We obtain polarizers with a dichroic ratio of up to 62, which is the highest value ever realized by a photoalignment method. Moreover, the polarizing thin film has a thickness of just 200 nm, compatible with flexible substrates, making it perfect for use as a dichroic polarizer in ultrathin and flexible displays

Weight Loss and Tar Evolution during Coal Devolatilization at Various Heating Rates

Temperature-resolved weight loss and tar yield during atmospheric devolatilization of pulverized coal have been obtained on a wire mesh reactor (WMR), which imposes prescribed thermal histories covering a wide range of heating rates on coals from lignite to anthracite. The accuracy of measurements has been improved by diminishing non-isothermality in the sample, ensuring independence of yields on loading density, and the development of a convenient tar collection method that inhibits secondary pyrolysis but also secures capture completeness. We reconfirm the continuous rank effects in terms of reaction dynamics and partitioning between tar and non-condensables but at disparate heating rates of 5 and 1000 K/s. In addition, we depict the constant variation in gas evolution histories among various coals before the cessation of tar release, whereas since the end of tar evolution, variations in gas formation kinetics for different coals gradually shrink with increasing temperatures. A larger fraction of total gases is found expelled after tar evolution by coals of higher rank. The sensitivity of the tar yield to heating rate is maintained the same over the range of 5–1000 K/s but varies with rank, being greatest for lignites and low-volatile bituminous coals but exhibiting a minimum for high-volatile bituminous coals

Effect of electrical stimulation combined with graphene-oxide-based membranes on neural stem cell proliferation and differentiation

The combination of composite nerve materials prepared using degradable polymer materials with biological or physical factors has received extensive attention as a means to treat nerve injuries. This study focused on the potential application of graphene oxide (GO) composite conductive materials combined with electrical stimulation (ES) in nerve repair. A conductive poly(L-lactic-co-glycolic acid) (PLGA)/GO composite membrane was prepared, and its properties were tested using a scanning electron microscope (SEM), a contact angle meter, and a mechanical tester. Next, neural stem cells (NSCs) were planted on the PLGA/GO conductive composite membrane and ES was applied. NSC proliferation and differentiation and neurite elongation were observed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, immunofluorescence, and PCR, respectively. The results showed that the PLGA/GO membrane had good hydrophilicity, mechanical strength, and protein adsorption. ES combined with the PLGA/GO membrane significantly promoted NSC proliferation and neuronal differentiation on the material surface and promoted significant neurite elongation. Our results suggest that ES combined with GO-related conductive composite materials can be used as a new therapeutic combination to treat nerve injuries.</p