Monotonicity results and bounds for the inverse hyperbolic sine

In this note, we present monotonicity results of a function involving to the inverse hyperbolic sine. From these, we derive some inequalities for bounding the inverse hyperbolic sine.Comment: 3 page

A fully dynamic multi-compartmental poroelastic system: Application to aqueductal stenosis

This study proposes the implementation of a fully dynamic four-network poroelastic model which is underpinned by multiple-network poroelastic theory (MPET), in order to account for the effects of varying stages of aqueductal stenosis and atresia during acute hydrocephalus. The innovation of the fully dynamic MPET implementation is that it avoids the commonplace assumption of quasi-steady behaviour; instead, it incorporates all transient terms in the casting of the equations and in the numerical solution of the resulting discrete system. It was observed that the application of mild stenosis allows for a constant value of amalgamated ventricular displacement in under 2.4 h, whereas the application of a severe stenosis delays this settlement to approximately 10 h. A completely blocked aqueduct does not show a clear sign of reaching a steady ventricular displacement after 24 h. The increasing ventricular pressure (complemented with ventriculomegaly) during severe stenosis is causing the trans-parenchymal tissue region to respond, and this coping mechanism is most attenuated at the regions closest to the skull and the ventricles. After 9 h, the parenchymal tissue shows to be coping well with the additional pressure burden, since both ventriculomegaly and ventricular CSF (cerebrospinal fluid) pressure show small increases between 9 and 24 h. Localised swelling in the periventricular region could also be observed through CSF fluid content, whilst dilation results showed stretch and compression of cortical tissue adjacent to the ventricles and skull

Developing N-Rich Carbon from C₃N₄-Polydopamine Composites for Efficient Oxygen Reduction Reaction

Nitrogen-rich carbon-based materials are amongst the most promising electrocatalysts for the oxygen reduction reaction (ORR) and/or the oxygen evolution reaction (OER). The introduction of nitrogen within the carbonaceous framework generates catalytic active sites and alters the electrical conductivity. However, the synthesis of these materials often involves long processes and severe reaction conditions which yield a low concentration of nitrogen (N) functionalities. Herein, we present a facile method for the synthesis of N-rich carbon by carbonizing a carbon nitride (C3N4)-polydopamine composite (CNDA) which can readily be prepared by room temperature self-polymerisation of dopamine in the presence of C3N4. The intrinsically high N content in C3N4 leads to a highly N-doped carbon. The CNDA catalyst synthesized at 900 °C contained 12.5 at% of N, enhancing both the ORR and OER catalytic activities through a 4-e− dominated pathway, providing a comparable E1/2 and a remarkably improved diffusion-limited current to the other reported N-doped carbon catalysts. When used as an air-cathode in a zinc-air battery, this CNDA catalyst possessed stable discharge-charge cycling performance for 216 h, outperforming the Pt/C standard. This work opens a promising platform for the development of template-free processes for the synthesis of non-metal and nitrogen-rich carbon materials which are attractive for metal-air batteries and fuel cells

Modeling aerobic biotransformation of vinyl chloride by vinyl chloride-assimilating bacteria, methanotrophs and ethenotrophs

© 2017 Elsevier B.V. Recent studies have investigated the potential of enhanced groundwater Vinyl Chloride (VC) remediation in the presence of methane and ethene through the interactions of VC-assimilating bacteria, methanotrophs and ethenotrophs. In this study, a mathematical model was developed to describe aerobic biotransformation of VC in the presence of methane and ethene for the first time. It examines the metabolism of VC by VC-assimilating bacteria as well as cometabolism of VC by both methanotrophs and ethenotrophs, using methane and ethene respectively, under aerobic conditions. The developed model was successfully calibrated and validated using experimental data from microcosms with different experimental conditions. The model satisfactorily describes VC, methane and ethene dynamics in all microcosms tested. Modeling results describe that methanotrophic cometabolism of ethene promotes ethenotrophic VC cometabolism, which significantly enhances aerobic VC degradation in the presence of methane and ethene. This model is expected to be a useful tool to support effective and efficient processes for groundwater VC remediation

A modeling approach to direct interspecies electron transfer process in anaerobic transformation of ethanol to methane

© 2016, Springer-Verlag Berlin Heidelberg. Recent studies have shown that direct interspecies electron transfer (DIET) plays an important part in contributing to methane production from anaerobic digestion. However, so far anaerobic digestion models that have been proposed only consider two pathways for methane production, namely, acetoclastic methanogenesis and hydrogenotrophic methanogenesis, via indirect interspecies hydrogen transfer, which lacks an effective way for incorporating DIET into this paradigm. In this work, a new mathematical model is specifically developed to describe DIET process in anaerobic digestion through introducing extracellular electron transfer as a new pathway for methane production, taking anaerobic transformation of ethanol to methane as an example. The developed model was able to successfully predict experimental data on methane dynamics under different experimental conditions, supporting the validity of the developed model. Modeling predictions clearly demonstrated that DIET plays an important role in contributing to overall methane production (up to 33 %) and conductive material (i.e., carbon cloth) addition would significantly promote DIET through increasing ethanol conversion rate and methane production rate. The model developed in this work will potentially enhance our current understanding on syntrophic metabolism via DIET

Microbial fuel cell for nutrient recovery and electricity generation from municipal wastewater under different ammonium concentrations

© 2019 Elsevier Ltd In the present study, a dual-compartment microbial fuel cell (MFC) was constructed and continuously operated under different influent concentrations of ammonium-nitrogen (5–40 mg/L). The impacts of ammonium on organics removal, energy output and nutrient recovery were investigated. Experimental results demonstrated that this MFC reactor achieved a CDO removal efficiency of greater than 85%. Moreover, excess ammonium concentration in the feed solution compromises the generation of electricity. Simultaneously, the recovery rate of phosphate achieved in the MFC was insignificantly influenced at the wider influent ammonium concentration. In contrast, a high concentration of ammonium may not be beneficial for its recovery

A novel mechanistic model for nitrogen removal in algal-bacterial photo sequencing batch reactors

© 2018 Elsevier Ltd A comprehensive mathematical model was constructed to evaluate the complex substrate and microbial interaction in algal-bacterial photo sequencing batch reactors (PSBR). The kinetics of metabolite, growth and endogenous respiration of ammonia oxidizing bacteria, nitrite oxidizing bacteria and heterotrophic bacteria were coupled to those of microalgae and then embedded into widely-used activated sludge model series. The impact of light intensity was considered for microalgae growth, while the effect of inorganic carbon was considered for each microorganism. The integrated model framework was assessed using experimental data from algal-bacterial consortia performing sidestream nitritation/denitritation. The validity of the model was further evaluated based on dataset from PSBR performing mainstream nitrification. The developed model could satisfactorily capture the dynamics of microbial populations and substrates under different operational conditions (i.e. feeding, carbon dosing and illuminating mode, light intensity, influent ammonium concentration), which might serve as a powerful tool for optimizing the novel algal-bacterial nitrogen removal processes

Comparing the value of bioproducts from different stages of anaerobic membrane bioreactors

© 2016 Elsevier Ltd The anaerobic digestion process in anaerobic membrane bioreactors is an effective way for waste management, energy sustainability and pollution control in the environment. This digestion process basically involves the production of volatile fatty acids and biohydrogen as intermediate products and methane as a final product. This paper compares the value of bioproducts from different stages of anaerobic membrane bioreactors through a thorough assessment. The value was assessed in terms of technical feasibility, economic assessment, environmental impact and impact on society. Even though the current research objective is more inclined to optimize the production of methane, the intermediate products could also be considered as economically attractive and environment friendly options. Hence, this is the first review study to correlate the idea into an anaerobic membrane bioreactor which is expected to guide future research pathways regarding anaerobic process and its bioproducts

Dynamical Axion Field in Topological Magnetic Insulators

Axions are very light, very weakly interacting particles postulated more than 30 years ago in the context of the Standard Model of particle physics. Their existence could explain the missing dark matter of the universe. However, despite intensive searches, they have yet to be detected. In this work, we show that magnetic fluctuations of topological insulators couple to the electromagnetic fields exactly like the axions, and propose several experiments to detect this dynamical axion field. In particular, we show that the axion coupling enables a nonlinear modulation of the electromagnetic field, leading to attenuated total reflection. We propose a novel optical modulators device based on this principle.Comment: 5 pages, 3 figure