Oxidative and Extractive Desulfurization of Fuel Oils Catalyzed by N-Carboxymethyl Pyridinium Acetate and N-Carboxyethyl Pyridinium Acetate Acidic Ionic Liquids: Experimental and Computational DFT Study.

This study reports on the synthesis, characterization, and application of two acidic ionic liquids, namely, N-carboxymethylpyridinium acetate ([HO2CCH2Py][CH3CO2] or AIL1) and N-carboxyethylpyridinium acetate ([HO2C(CH2)2Py][CH3CO2] or AIL2), as both extractants and catalysts for the oxidative and extractive desulfurization (OEDS) of model fuel oils containing heteroaromatic sulfur compounds. The structural properties of the synthesized acidic ionic liquids (ILs) were confirmed by 1H NMR, 13C NMR, and FT-IR spectroscopic analysis. To optimize the performance of the acidic AILs in the desulfurization process, the effects of different parameters, such as H2O2 dosage, reaction time, and temperatures, were investigated. The experimental results showed that AIL1 has exceptionally high desulfurization-extraction rates, with values of 99.8%, 97.8%, and 95.4%, for DBT, BT, and 4,6-DMDBT, respectively, under the optimum conditions established. Under the same conditions, the desulfurization-extraction rates using AIL2 reached 91.6%, 87.3%, and 82.4%, respectively, for DBT, 4, 6-DMDBT, and BT. Both ionic liquids can be recycled up to 9 times without a significant decrease in their sulfur removal efficiencies. Furthermore, density functional theory (DFT) calculations were conducted to evaluate the electronic interaction energies (ΔIE) between the AILs with each of the sulfur-containing compounds and their putative oxidized products. The computational findings strongly supported the experimental outcomes.

Hysteresis of wettability in porous media: a review.

The process of "hysteresis" has widely attracted the attention of researchers and investigators due to its usage in many disciplines of science and engineering. Economics, physics, chemistry, electrical, mechanical, and petroleum engineering are some examples of disciplines that encounter hysteresis. However, the meaning of hysteresis varies from one field to another, and therefore, many definitions occur for this phenomenon depending on the area of interest. The "hysteresis" phenomenon in petroleum engineering has gained the attention of researchers and investigators lately, because of the role that plays in reservoir engineering and reservoir simulation. Hysteretic effects influence reservoir performance. Therefore, an accurate estimation of rock and fluid property curves has an essential role in evaluating hydrocarbon recovery processes. In this paper, a comprehensive review of research and growth on the hysteresis of wettability for its applications in petroleum engineering is reported. Also, theoretical and experimental investigations of hysteresis of wettability are compared and discussed in detail. The review highlights a range of concepts in existing models and experimental processes for wettability hysteresis. Furthermore, this paper tracks the current development of hysteresis and provides insight for future trends in the research. Finally, it reveals an outlook on the research challenges and weaknesses of hysteresis of wettability.

Fractional order model identification using the sinusoidal input.

An output error optimization approach for identification of parsimonious fractional order models using multi-frequency sinusoids as input is proposed. The algorithm simultaneously estimates orders, parameters and the delay of simple models with fractional orders using the Gauss-Newton optimization approach. Optimization-based methods for fractional order model identification require evaluation of the sensitivity functions which include the logarithmic derivatives of the input signal. In the existing literature, central difference or similar methods are used to numerically calculate the Jacobian matrix due to difficulties with numerical simulation of the logarithmic derivatives. We assume deterministic input signals and provide analytical expressions for the logarithmic derivatives of single and multiple frequency sinusoids. Relevant mathematical derivations are presented and the analytical expressions are used to evaluate the Jacobian. Effects of noise to signal ratio, input frequency and sampling intervals are studied in simulation to demonstrate the efficacy of the method. Convergence and robustness of the method is also studied. In theory, the approach is applicable for models with large set of parameters; however, convergence of the optimization scheme needs to be addressed.

TaiNi: Maximizing research output whilst improving animals' welfare in neurophysiology experiments.

Understanding brain function at the cell and circuit level requires representation of neuronal activity through multiple recording sites and at high sampling rates. Traditional tethered recording systems restrict movement and limit the environments suitable for testing, while existing wireless technology is still too heavy for extended recording in mice. Here we tested TaiNi, a novel ultra-lightweight (<2 g) low power wireless system allowing 72-hours of recording from 16 channels sampled at ~19.5 KHz (9.7 KHz bandwidth). We captured local field potentials and action-potentials while mice engaged in unrestricted behaviour in a variety of environments and while performing tasks. Data was synchronized to behaviour with sub-second precision. Comparisons with a state-of-the-art wireless system demonstrated a significant improvement in behaviour owing to reduced weight. Parallel recordings with a tethered system revealed similar spike detection and clustering. TaiNi represents a significant advance in both animal welfare in electrophysiological experiments, and the scope for continuously recording large amounts of data from small animals.