On the role of resonantly stabilized radicals in polycyclic aromatic hydrocarbon (PAH) formation: pyrene and fluoranthene formation from benzyl-indenyl addition.

Resonantly stabilized radicals, such as propargyl, cyclopentadienyl, benzyl, and indenyl, play a vital role in the formation and growth of polycyclic aromatic hydrocarbons (PAHs) that are soot precursors in engines and flames. Pyrene is considered to be an important PAH, as it is thought to nucleate soot particles, but its formation pathways are not well known. This paper presents a reaction mechanism for the formation of four-ring aromatics, pyrene and fluoranthene, through the combination of benzyl and indenyl radicals.

Computational Predictions for Single Chain Chalcogenide-Based One-Dimensional Materials.

Exfoliation of multilayered materials has led to an abundance of new two-dimensional (2D) materials and to their fabrication by other means. These materials have shown exceptional promise for many applications. In a similar fashion, we can envision starting with crystalline polymeric (multichain) materials and exfoliate single-chain, one-dimensional (1D) materials that may also prove useful.

A hybrid energy model for region based curve evolution - Application to CTA coronary segmentation.

Background And Objective: State-of-the-art medical imaging techniques have enabled non-invasive imaging of the internal organs. However, high volumes of imaging data make manual interpretation and delineation of abnormalities cumbersome for clinicians. These challenges have driven intensive research into efficient medical image segmentation.

Computational study of ibuprofen removal from water by adsorption in realistic activated carbons.

Molecular simulations using the Grand Canonical Monte Carlo (GCMC) method have been performed in order to obtain physical insights on how the interaction between ibuprofen (IBP) and activated carbons (ACs) in aqueous mixtures affects IBP removal from water by ACs. A nanoporous carbon model based on units of polyaromatic molecules with different number of rings, defects and polar-oxygenated sites is described. Individual effects of factors such as porous features and chemical heterogeneities in the adsorbents are investigated and quantified.

Machine learning in the prediction of cardiac epicardial and mediastinal fat volumes.

We propose a methodology to predict the cardiac epicardial and mediastinal fat volumes in computed tomography images using regression algorithms. The obtained results indicate that it is feasible to predict these fats with a high degree of correlation, thus alleviating the requirement for manual or automatic segmentation of both fat volumes. Instead, segmenting just one of them suffices, while the volume of the other may be predicted fairly precisely.

The phase and interfacial properties of azeotropic refrigerants: the prediction of aneotropes from molecular theory.

The use of hydrofluorocarbons (HFCs) as alternative non-ozone depleting refrigerants for chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) has grown during the last couple of decades. Owing to their considerable global warming potential, a global deal has been reached recently to limit the production and consumption of HFCs. For rational design of new refrigerants that are environmentally friendlier, the thermodynamics of current ones need to be well understood first.

Ionic liquids and deep eutectic solvents for lignocellulosic biomass fractionation.

Lignocellulosic biomass has gained extensive research interest due to its potential as a renewable resource, which has the ability to overtake oil-based resources. However, this is only possible if the fractionation of lignocellulosic biomass into its constituents, cellulose, lignin and hemicellulose, can be conducted more efficiently than is possible with the current processes. This article summarizes the currently most commonly used processes and reviews the fractionation with innovative solvents, such as ionic liquids and deep eutectic solvents.

Food wastes derived adsorbents for carbon dioxide and benzene gas sorption.

Food wastes are produced worldwide in large quantities that could have potential to produce higher value products, including industrial adsorbents. The present work attempts valorization of food waste by CO activation and functionalization through nitric acid and melamine treatment. The prepared porous materials were subjected to gas phase adsorption of CO and benzene gases.

A comparison of ultrasound-augmented and conventional leaching of silver from sintering dust using acidic thiourea.

In the process of steel manufacture, up to ten millions of tons of sintering dust (SD) are produced annually in China, which contain noble metals such as Ag. Therefore, recovery of silver (Ag) from SD could be a potential economic and environmental activity. The purpose of this article is to generate information about reaction kinetics of silver leaching with thiourea from SD, comparing the conventional and ultrasonic-augment leaching.

Removal of alkali and transition metal ions from water with hydrophobic deep eutectic solvents.

Hydrophobic deep eutectic solvents were used for the first time for the removal of metal ions from non-buffered water. It was shown that the extraction occurs via an ion exchange mechanism in which all transition metal ions could be extracted with high distribution coefficients, even for high Co concentrations and low DES/water mass ratios. Maximum extraction efficiency could be reached within 5 s and regeneration was possible.

Probing Grain-Boundary Chemistry and Electronic Structure in Proton-Conducting Oxides by Atom Probe Tomography.

A laser-assisted atom-probe-tomographic (LAAPT) method has been developed and applied to measure and characterize the three-dimensional atomic and electronic nanostructure at an yttrium-doped barium zirconate (BaZrYO, BZY10) grain boundary. Proton-conducting perovskites, such as BZY10, are attracting intense interest for a variety of energy conversion applications. However, their implementation has been hindered, in part, because of high grain-boundary (GB) resistance that is attributed to a positive GB space-charge layer (SCL).

Ag and Cu Monometallic and Ag/Cu Bimetallic Nanoparticle-Graphene Composites with Enhanced Antibacterial Performance.

Increased proliferation of antimicrobial resistance and new strains of bacterial pathogens severely impact current health, environmental, and technological developments, demanding design of novel, highly efficient antibacterial agents. Ag, Cu monometallic and Ag/Cu bimetallic nanoparticles (NPs) were in situ grown on the surface of graphene, which was produced by chemical vapor deposition using ferrocene as precursor and further functionalized to introduce oxygen-containing surface groups. The antibacterial performance of the resulting hybrids was evaluated against Escherichia coli cells and compared through a series of parametrization experiments of varying metal type and concentration.

Examining Asphaltene Solubility on Deposition in Model Porous Media.

Asphaltenes are known to cause severe flow assurance problems in the near-wellbore region of oil reservoirs. Understanding the mechanism of asphaltene deposition in porous media is of great significance for the development of accurate numerical simulators and effective chemical remediation treatments. Here, we present a study of the dynamics of asphaltene deposition in porous media using microfluidic devices.

Thermophysical properties of imidazolium tricyanomethanide ionic liquids: experiments and molecular simulation.

The low-viscous tricyanomethanide ([TCM](-))-based ionic liquids (ILs) are gaining increasing interest as attractive fluids for a variety of industrial applications. The thermophysical properties (density, viscosity, surface tension, electrical conductivity and self-diffusion coefficient) of the 1-alkyl-3-methylimidazolium tricyanomethanide [Cnmim][TCM] (n = 2, 4 and 6-8) IL series were experimentally measured over the temperature range from 288 to 363 K. Moreover, a classical force field optimized for the imidazolium-based [TCM](-) ILs was used to calculate their thermodynamic, structural and transport properties (density, surface tension, self-diffusion coefficients, viscosity) in the temperature range from 300 to 366 K.

Degradable polyethylene nanocomposites with silica, silicate and thermally reduced graphene using oxo-degradable pro-oxidant.

Polyethylene nanocomposites with silica, alumino-silicate and thermally reduced graphene were generated by adding pro-oxidant additive. Additive resulted in early degradation of pure polymer, however, the degradation was delayed in the presence of fillers. Graphene resulted in maximum extent of enhancement of peak degradation temperature (13-14 °C depending on the additive content) followed by silicate and silica.

Patient-Specific Computational Models of Coronary Arteries Using Monoplane X-Ray Angiograms.

Coronary artery disease (CAD) is the most common type of heart disease in western countries. Early detection and diagnosis of CAD is quintessential to preventing mortality and subsequent complications. We believe hemodynamic data derived from patient-specific computational models could facilitate more accurate prediction of the risk of atherosclerosis.

Understanding acoustic methods for cement bond logging.

Well cementation is important for oil/gas production, underground gas storage, and CO2 storage, since it isolates the reservoir layers from aquifers to increase well integrity and reduce environmental footprint. This paper analyzes wave modes of different sonic/ultrasonic methods for cement bonding evaluation. A Two dimensional finite difference method is then used to simulate the wavefield for the ultrasonic methods in the cased-hole models.

Polycyclic aromatic hydrocarbon (PAH) formation from benzyl radicals: a reaction kinetics study.

The role of resonantly stabilized radicals such as propargyl, cyclopentadienyl and benzyl in the formation of aromatic hydrocarbons such as benzene and naphthalene in the high temperature environments has been long known. In this work, the possibility of benzyl recombination to form three-ring aromatics, phenanthrene and anthracene, is explored. A reaction mechanism for it is developed, where reaction energetics are calculated using density functional theory (B3LYP functional with 6-311++G(d,p) basis set) and CBS-QB3, while temperature-dependent reaction kinetics are evaluated using transition state theory.

PC-SAFT Modeling of CO2 Solubilities in Deep Eutectic Solvents.

Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT), a physically based model that accounts for different molecular interactions explicitly, was applied to describe for the first time the phase behavior of deep eutectic solvents (DESs) with CO2 at temperatures from 298.15 to 318.15 K and pressures up to 2 MPa.

Facile In Situ Fabrication of Nanostructured Graphene-CuO Hybrid with Hydrogen Sulfide Removal Capacity.

A simple and scalable synthetic approach for one-step synthesis of graphene-CuO (TRGC) nanocomposite by an in situ thermo-annealing method has been developed. Using graphene oxide (GO) and copper hydroxide as a precursors reagent, the reduction of GO and the uniform deposition of in situ formed CuO nanoparticles on graphene was simultaneously achieved. The method employed no solvents, toxic-reducing agents, or organic modifiers.

RTDS implementation of an improved sliding mode based inverter controller for PV system.

This paper proposes a novel approach for testing dynamics and control aspects of a large scale photovoltaic (PV) system in real time along with resolving design hindrances of controller parameters using Real Time Digital Simulator (RTDS). In general, the harmonic profile of a fast controller has wide distribution due to the large bandwidth of the controller. The major contribution of this paper is that the proposed control strategy gives an improved voltage harmonic profile and distribute it more around the switching frequency along with fast transient response; filter design, thus, becomes easier.

Synthesis of porous sulfonated carbon as a potential adsorbent for phenol wastewater.

The work reports a facile synthesis procedure for preparation of porous sulfonated carbons and its suitability for adsorption of phenol. The sulfonated carbon was synthesized utilizing a simplified, single-step, shorter duration process by sulfonation, dehydration and carbonization of sucrose in sulfuric acid and tetraethylorthosilicate. The surface and internal structures of the adsorbents were characterized utilizing various characterization techniques to understand the porous nature and surface functional groups of the porous matrix.

How Sensitive Is the Elasticity of Hydroxyapatite-Nanoparticle-Reinforced Chitosan Composite to Changes in Particle Concentration and Crystallization Temperature?

Hydroxyapatite (HA) nanoparticle-reinforced chitosan composites are biocompatible and biodegradable structural materials that are used as biomaterials in tissue engineering. However, in order for these materials to function effectively as intended, e.g.