Pore-Level Investigation of Heavy Oil Recovery During Water Alternating Solvent Injection Process

This study concerns with the microscopic and macroscopic fluid distribution and flow behavior during water alternating solvent (WAS) injection process to heavy oil using micromodel generated from thin section of a real rock which has rarely attended in the available literature. In this study, a one-quarter five-spot glass micromodel was deployed to examine the effect of flow media topology on microscopic displacements as well as macroscopic efficiency of WAS process. The micromodel was initially saturated with the heavy oil, and then the hydrocarbon solvent and water were injected alternately into it. The observations confirmed that WAS injection scheme is an effective method for the recovery of the significant amount of residual oil. Using solvent as the leading batch in WAS scheme can really improve the oil recovery by increasing the amount of microscopic sweep efficiency in flow paths, where the molecular diffusion in solvent–heavy oil system occurs. Presence of connate water in WAS scheme can improve the recovery efficiency especially at higher water saturations. Heterogeneity of the medium caused the water to be distributed better in the medium, but the amount of residual oil in the flow area is going to be increased. Small precipitates of asphaltene particles due to solvent injection and localized entrapment of the oil due to heterogeneity effects, water blockage, and deadend pores were observed mainly in this process. The results of this study reveals the pore scale events in WAS injection process and will be helpful for developing reliable simulation models.     

Thermal effect on superhydrophobic performance of stearic acid modified ZnO nanotowers

The thermal desorption of stearic acid on superhydrophobic zinc oxide nanotowers has been investigated. The stearic acid passivated zinc oxide nanotowers provide a very high contact angle of ∼173 ± 1.1° with a very low hysteresis of ∼1.4 ± 0.5° due to the presence of a binary structure composed of several nanosteps on each nanotower of height ∼700 nm that eventually reduces the area of contact between the drop and the nanotowers and trapping more air as revealed by the field emission scanning electron microscopy images. The superhydrophobic performance of these nanotowers, however, declines following annealing at elevated temperatures. Fourier transform infrared spectra show a reduction in the intensity of stearic acid -CH_n peaks at elevated temperatures revealing the cause of the decrease in contact angle and confirming the occurrence of thermal desorption at 184 °C. The corresponding activation energy for desorption determined from our data is 0.34 ± 0.05 eV. It is found that the stearic acid has completely disappeared at 350 °C, making the sample hydrophilic.     

A note on strong skew Jordan product preserving maps on von Neumann algebras

Periodica Mathematica Hungarica - Let $$\mathcal {A}$$ be a von Neumann algebra acting on the complex Hilbert space $$\mathcal {H}$$ and $$\Phi {:}\,\mathcal {A} \longrightarrow \mathcal {A}$$ be a...     

Multi-objective optimization of pin fin to determine the optimal fin geometry using genetic algorithm

In this study, one dimensional heat transfer in a pin fin is modeled and optimized. We used Bezier curves to determine the best geometry of the fin. The model equations are solved to analyze the heat transfer. Total heat transfer rate and fin efficiency factor are considered as two objective functions and multi-objective optimization carried out to maximize heat transfer rate and fin efficiency simultaneously. Fast and elitist non-dominated sorting genetic algorithm (NSGA-II) is used to determine a set of multiple optimum solutions, called ‘Pareto optimal solutions. The optimized results are presented with Pareto front which demonstrate conflict between two objective functions in the optimized point, both energy conservation and thermal analysis are carried out to verify the solution method and the results shows good precision.     

Anti-icing performance of superhydrophobic surfaces

This article studies the anti-ice performance of several micro/nano-rough hydrophobic coatings with different surface chemistry and topography. The coatings were prepared by spin-coating or dip coating and used organosilane, fluoropolymer or silicone rubber as a top layer. Artificially created glaze ice, similar to the naturally accreted one, was deposited on the nanostructured surfaces by spraying supercooled water microdroplets (average size ∼80 μm) in a wind tunnel at subzero temperature (−10 °C). The ice adhesion strength was evaluated by spinning the samples in a centrifuge at constantly increasing speed until ice delamination occurred. The results show that the anti-icing properties of the tested materials deteriorate, as their surface asperities seem to be gradually broken during icing/de-icing cycles. Therefore, the durability of anti-icing properties appears to be an important point for further research. It is also shown that the anti-icing efficiency of the tested superhydrophobic surfaces is significantly lower in a humid atmosphere, as water condensation both on top and between surface asperities takes place, leading to high values of ice adhesion strength. This implies that superhydrophobic surfaces may not always be ice-phobic in the presence of humidity, which can limit their wide use as anti-icing materials.     

Efficient One‐Pot Synthesis of β‐Acetamido Carbonyl Compounds Using Fe3O4 Nanoparticles

A new, one‐pot condensation of aldehydes, enolizable ketones and esters, AcCl, and MeCN, in the presence of Fe₃O₄ nanoparticles (nano‐Fe₃O₄) as an efficient catalyst, for the preparation of β‐acetamido carbonyl compounds at room temperature is described.     

Highly Substituted Δ3-1,2,3-Triazolines: Solid-State Emitters with Electrofluorochromic Behavior

Highly substituted Δ³-1,2,3-triazolines can be prepared by reaction of triarylvinyl Grignard reagents with functionalized organic azides. The heterocycles are fluorescent in the solid state, and—depending on the substituents—they can display aggregation-induced emission. Upon oxidation, the triazolines form stable radical cations with altered photophysical properties. Therefore, they represent rare examples of solid-state emitters with intrinsic electrofluorochromic behavior.     

Nano- and micro-structure tin (IV) complexes bearing 4-pyridinecarbacylamidophosphate: Sonochemical synthesis,crystal structure,anti-cholinesterase activity,and docking studies

Two di- and triorganotin (IV) complexes, Sn (CH₃)₂Cl₂(4-PCAPh)₂ ( C ₁ ) and Sn(C₆H₅)₃Cl(4-PCAPh) ( C ₂ ); {4-PCAPh = 4-NC₅H₄C(O)NHP(O)(C₆H₁₂N)₂}, have been synthesized and characterized by elemental analysis, ¹H, ¹³C, ³¹P NMR and IR spectroscopy. The crystal structure of C ₁ has been confirmed by X-ray crystallography, which reveals an octahedral geometry surrounding Sn (IV). Both ligands function in an all-trans conformation, with an N-ligated mode for 4-PCAPh. Also, the complexes were prepared at nano- ( Ć ₁ ) and micro-size ( Ć ₂ ) by the sonochemical process. The role of reaction solvent and the concentration of initial reactants on the size and morphology of particles were studied and the products were characterized by X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). The activities and mechanism of complexes C ₁ , C ₂ , Ć ₁ , Ć ₂ and their corresponding ligand ( L ) on cholinesterase (ChE) were evaluated using a modified Ellman's method and Lineweaver-Burk plots. Nanosheet Ć ₁ showed the best activity against AChE and BChE with the IC₅₀ values being 73.08 ± 0.12 μM and 122.48 ± 0.69 μM, respectively, and the mixed-type mechanism. Molecular modeling simulation revealed the binding interaction template for Sn (CH₃)₂Cl₂(4-PCAPh)₂ with the ChE.     

Pseudocapacitive Lithium Storage of Cauliflower-Like CoFe2O4 for Low-Temperature Battery Operation

Binary transition-metal oxides (BTMOs) with hierarchical micro–nano-structures have attracted great interest as potential anode materials for lithium-ion batteries (LIBs). Herein, we report the fabrication of hierarchical cauliflower-like CoFe₂O₄ (cl-CoFe₂O₄) via a facile room-temperature co-precipitation method followed by post-synthetic annealing. The obtained cauliflower structure is constructed by the assembly of microrods, which themselves are composed of small nanoparticles. Such hierarchical micro–nano-structure can promote fast ion transport and stable electrode–electrolyte interfaces. As a result, the cl-CoFe₂O₄ can deliver a high specific capacity (1019.9 mAh g⁻¹ at 0.1 A g⁻¹), excellent rate capability (626.0 mAh g⁻¹ at 5 A g⁻¹), and good cyclability (675.4 mAh g⁻¹ at 4 A g⁻¹ for over 400 cycles) as an anode material for LIBs. Even at low temperatures of 0 °C and −25 °C, the cl-CoFe₂O₄ anode can deliver high capacities of 907.5 and 664.5 mAh g⁻¹ at 100 mA g⁻¹, respectively, indicating its wide operating temperature. More importantly, the full-cell assembled with a commercial LiFePO₄ cathode exhibits a high rate performance (214.2 mAh g⁻¹ at 5000 mA g⁻¹) and an impressive cycling performance (612.7 mAh g⁻¹ over 140 cycles at 300 mA g⁻¹) in the voltage range of 0.5–3.6 V. Kinetic analysis reveals that the electrochemical performance of cl-CoFe₂O₄ is dominated by pseudocapacitive behavior, leading to fast Li⁺ insertion/extraction and good cycling life.     

Metal organic framework–derived core-shell CuO@NiO nanosphares as hole transport material in perovskite solar cell

Journal of Solid State Electrochemistry - Cu-Ni bimetallic organic frameworks were synthesized by a facile and stepwise solvothermal method, utilizing metal organic framework as precursor....