查看更多>>摘要：Currently, fossil fuels are considered the primary energy carriers having a significant role in the global energy market. Two main features, including environmental pollution owing to greenhouse gas emissions as well as fossil fuel reserves depletion, make severe instability in the world market. Consequently, researchers are trying to propose different processes to attain energy from renewable sources. In this study, a novel heat exchanger reactor for sustainable hydrogen production from glycerol steam reforming has been suggested. In this configuration, the required heat of steam reforming reactions is supplied through the catalytic combustion reaction. At the same time, the required fuel for the combustion reactions is provided by reforming side by-products. A one-dimensional mathematical model has been developed to study the reactor behavior and the role of different influencing parameters on its performance. The results showed that it is feasible to eliminate the furnace used in the conventional process and enhance the glycerol conversion by 48% compared to the adiabatic reactor. Since the use of byproducts of the glycerol steam reforming as a heat source for the hydrogen production has not been used so far, it can be acknowledged that this method could be feasible and beneficial in energy saving.
查看更多>>摘要：Guava leaves contain polyphenols, which exhibit antioxidant activities and act as electron suppliers. It was postulated that guava leaf extract (GLE) may have the potential to be used as a natural reducing agent for in situ chemical reduction of chlorinated solvents, such as carbon tetrachloride (CT). Extraction of GLE was conducted by boiling guava leaves, and filtering the liquid to produce GLE-Filtrate. GLE-Powder was produced by drying the GLE-Filtrate at 50 °C Characterization analysis showed a yield of 16.6 g GLE-Powder/100 g of leaves, with a total polyphenolic content of 300 mg g~(-1) and with gallocatechin as a major constituent. Both GLE-Powder and GLE-Filtrate exhibited the capability to degrade CT in aqueous phase. The CT degradation rate increased with increasing alkaline conditions, at pH higher than the pl<a of polyphenols. GLE-Filtrate reductive degradation of CT can be enhanced with the presence of iron salts, and various minerals, or soils containing iron, at pH 10. The specific surface area rate constant (k_(SA)) of CT degradation for the GLE-Filtrate/Fe2O3 aqueous system was as high as 5.52 x 10~(-3) L d~(-1) m~(-2). The analysis of byproducts formation found trichloromethane to be a major intermediate, which was further mineralized to generate CI".
查看更多>>摘要：Lipid nanoparticles (LNPs) have been widely used in drug delivery systems. Their physicochemical properties play a substantial role in the pharmaceutical functions and therapeutic efficacy of encapsulated drugs. Although, numerous previous studies have examined the optimal physicochemical properties for drug delivery, the role of LNP mechanical compliance has not yet been established, owing to limitations imposed by their small size, extreme softness, and complex structures. The aim of this study was to delineate the true topography and the map of elastic moduli of LNPs by analyzing atomic force microscope (AFM) force spectroscopic data based on the modified Hertz model considering the asymptotic approach. Results reveal a hard core-soft shell structure of LNPs. Additionally, the elastic moduli of the core of LNPs are modulated from 176 kPa to 599 kPa through the addition of crosslinked alginate. However, a consistent elastic modulus (~128 kPa) of outer shells is maintained regardless of core composition. In addition, Transwell assay show that, compared to rigid LNPs, those with soft properties exhibit enhanced permeation. This finding, which delineates the true topography and elastic moduli of LNPs, suggest an alternative for resolving the long-standing issues in AFM force spectroscopic studies.
查看更多>>摘要：The use of coaxial mixers has significantly improved gas dispersion in non-Newtonian fluids. However, to the best of our knowledge, no scale-up investigation of an aerated coaxial mixer has been reported in the literature. This study aims to explore the gas hold-up, energy dissipation rate, power consumption and cavity size in order to provide the guideline for scaling-up of the coaxial mixers. Through the use of computational fluid dynamics and electrical resistance tomography, the effects of the aeration rate, central impeller type, rotating mode, impeller speed, and pumping direction on the gas dispersion efficacy in both small-scale and large-scale coaxial mixers containing non-Newtonian fluids were investigated. For the coaxial mixer in the co-rotating mode, the same flow regime was achieved when the central impeller tip speed and the anchor impeller rotational speed were kept constant in both small-scale and large-scale systems. It was observed that maintaining the aeration rate per volume of the non-Newtonian fluid constant was beneficial to preserve the performance of the large-scale coaxial mixer the same as its small-scale counterpart. The use of specific power consumption as a scale up criterion effectively improved the energy dissipation rate uniformity, which is critical for shear sensitive applications.
查看更多>>摘要：Probing effective, highly active, and inexpensive electrocatalysts for oxygen evolution reaction (OER) is of immense importance for water electrolysis. Transition metal chalcogenides have been developed as a new class of materials for energy storage and conversion owing to their distinctive properties, such as capacitance, conductivity, and redox behavior. Three-dimensional carbon cloth (CC), is a unique carbon network with extraordinary flexibility, mechanical stability, and high conductivity for application in energy-conversion systems. In this study, we designed ruthenium cobalt sulfide over a carbon cloth (RuCoS2/CC) via electrodeposition followed by an immersion technique and applied it for the OER. The molar ratio for Ru (amount of Ru-10, 20, 30 mg & immersion time-3, 6, and 9 h), Co (0.05 to 0.3 M), and S (0.05 to 0.2 M) precursors were optimized. Owing to the existence of binary active sites, heteroatoms, and synergetic effect between the transition metal chalcogenides and the carbon substrate, Ru (20 mg immersed for 6 h) at CoS2 (Co-0.2 M & S2-0.05 M) modified CC (shortly denoted as RuCoS2/ CC) exhibits a lower overpotential (315 mV), better Tafel slope (74 mV dec~(-1)), and excellent durability (retention rate-94.64%) compared with CoS2/CC and previous studies. Therefore, RuCoS2/CC is perceived to show better OER performance in the electrocatalysis of water.
查看更多>>摘要：Electrochemical reduction of CO2 is regarded as a promising technique for converting unwanted CO2 into high-value chemicals. Among the various electrocatalysts that are crucial for overcoming sluggish reduction processes, Zn has been continuously studied because of its suitable catalytic activity and abundance in the earth's crust. In this study, we fabricated highly porous foam-like Zn nanostructures on a gas diffusion layer (GDL) using hydrothermal growth and in situ reduction process. The prepared electrode showed a CO partial current density of 20.9 mA-cmr2 at-1.10 V, which is approximately 10 times higher than that of the bare Zn foil. Moreover, the fabricated electrode can be directly applied to the large-scale flow cell system without further modification. The flow cell system with the fabricated electrode showed a current density of approximately 200 mA-cm~(-2) and CO faradaic efficiency of 75% on a 2 h long experiment at 2.7 V cell voltage, which clearly confirms the possibility of highly porous Zn nanostructures on GDL.
查看更多>>摘要：A novel thermally stable inhibitor was developed based on citric acid and glucose (CAGCI) to inhibit the corrosion of mild steel (MS) in simulated acidic oilfield water for oil well acidizing. All electrochemical measurements were performed in a temperature range of 293-363 K to evaluate the inhibition power of CAGCI. The results of electrochemical tests clearly revealed that CAGCI effectively inhibited MS corrosion via a mixed-type mechanism and 77 x 10~(-4) M of the inhibitor provided the highest inhibition efficiency of 90%, 93.6%, 93.7%, and 89.9% at 293 K, 313 K, 333 K, and 363 K, respectively. In addition, CAGCI provided a total polarization resistance of 416.7 Ω. cm~2 for MS at 293 K and decreased the corrosion rate of the metal 7.6 times compared to blank at 363 K. Moreover, the UV-visible results demonstrated the formation of the Fe~(2+)-CAGCI complex and the results of the surface analysis confirmed the presence of a protective film of CAGCI molecules on the MS surface. Finally, the experimental outcomes were well complemented by results obtained from density-functional study and molecular dynamics (MD) simulation. According to quantum calculations, citric acid and aromatic rings in the structure of CAGCI played the main role in electron exchanges with the MS surface. The results of the MD simulation were also confirmed that a hydrophobic barrier can be formed by CAGCI molecules on the MS surface with a parallel adsorption configuration.
查看更多>>摘要：Imidazo-pyridazine and Bromo/Chloro-Imidazo-pyridazines are employed as the inhibitors for Al alloy in 0.1 M HC1 and 0.5 M HC1 solutions. The electrochemical tests and adsorption model analysis revealed that three compounds are mixed-type inhibitors and Imidazo-pyridazine exhibited the best anti-corrosion performance for Al electrode in HC1 solutions by physicochemical. From electrochemical results, the best anti-corrosion efficiency is 88.1 % for Al in 0.5 M HCI with 2.0 mM IP, while the efficiency is 75.5 % for Al in 0.5 M HCI with 1.0 mM IP. The different inhibition behaviors result from the probability of the formation of AlCl_(ads) and N-onium ions. The formation of adsorption is due to the electrostatic attraction between AlCl_(ads) and N-onium ions. The surface topography test revealed that the Imidazo-pyridazine is the best corrosion barrier for Al in 0.5 M HCI. The dynamic simulation demonstrated that the inhibition molecules and protonated molecules can adsorb on the Al surface spontaneously with parallel adsorption configuration no matter in more or less CI" atmosphere.
查看更多>>摘要：Insensitive munitions (IMs) that suit safety requirements have received much attention to prevent an accidental explosion of the munition by external stimuli. For example, l,3,5-trinitro-l,3,5-triazinane (RDX), a sensitive legacy explosive material with high explosive performance, is usually used together with insensitive explosives such as 2,4,6-triamino-l,3,5-trinitrobenzene (TATB) in IM formulation to fit the safe operational range of sensitivities. In recent decades, the development of new high energy materials (HEMs) with remarkable insensitivities have become a forefront topic of the energetic material field. Herein, we report a novel HEM based on a hexaaza[3.3.3]propellane skeleton, 2,6-dinitro-3,7,10-trioxo-2,4,6,8,9,ll-hexaaza[3.3.3]pro-pellane (5), which was determined to have high explosive performance along with reduced sensitivity to external stimuli. Both the measured explosive performances and the impact sensitivity of 5 were better than those of TATB. We propose 5 as a promising insensitive HEM and a potential candidate for IM.
查看更多>>摘要：The porous cellulose materials are fabricated from cellulose acetate (CA) and Na salts. When composite films consisting of CA and NaNO3 are exposed to water-pressure, the maximum flux reached to 8.6 L m~(-2)h~(-1). The generated water flux is attributable to the partial plasticization in polymer chains by hydrated NaNO3. The flexible polymer chains by hydrated salts can be the pores by external physical forces. Surprisingly, the CA/NaNO3 film shows a high porosity of 78.15 % and pore shapes was confirmed via scanning electron microscopy. Moreover, it preserves the excellent heat resistance properties, confirmed by thermal gravimetric analysis.
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