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Hide R-CNN-based creating removing through VHR satellite data throughout operational humanitarian actions: One example in connection with Covid-19 response in Khartoum, Sudan.
The water diffusion rate inside the annealed microsphere was twice as fast as for unannealed counterparts. The findings relate the overall phase and pore structure change of the microsphere to the increased drug release induced by annealing. This work serves as a basis for the rational understanding of the modification of the in vitro performance by annealing, a widely used post-process for solid lipid products. Bubbles are one of the primary sources of transferring substances from water to air. When bubbles burst, small droplets containing microparticles and microorganisms previously suspended in water disperse. Hence, visualizing small objects in bubble films can provide a new methodology for investigating the material transfer from water to the environment and the dynamic behavior of objects in the films. We used Schlieren imaging of bubbles to visualize small objects such as bacteria and microplastics. Remarkably, black spots (Schlieren spots) appeared when light rays passed parallel to bubbles formed on the water containing microparticles and bacteria. The simulation method of Schlieren imaging of bubbles was developed to clarify the underlying mechanism and experimentally validated with different sizes and concentrations of microparticles. We found that a specific water meniscus is formed around a particle when the bubble film thickness is smaller than the particle diameter, and the meniscus plays an important role in enlarging the Schlieren spots. The Schlieren spots are forty times larger than the bubble film thickness in this work. To understand the magnification rule, we illuminated the correlation between bubble film thickness, particle diameter, and Schlieren spot diameter. Layered transition metal oxides have a potential as catalysts for biomass conversions or as adsorbents. A better understanding of their properties is thus necessary, notably in liquid phase, where these materials have the specificity to intercalate molecules within their interlayers. To discriminate between potential catalysts or adsorbents, it is desirable to study the surface properties in the conditions of intercalation. The intercalation behaviour and acidity of four different acidic layered materials pure tungstate phases H2W2O7, H2WO4 and mixed oxides HNbWO6 and HNbMoO6 have thus been investigated directly in liquid phase. Besides Powder X-ray diffraction, Raman spectroscopy provided valuable informations first during the preliminary protonation step and second by monitoring both the intercalation of liquid organic bases and the accessible acidity. N-alkylamines such as butylamine and octylamine were found unsuitable to discriminate the layered solids while pyridine was more selective. Pyridine did not intercalate in H2W2O7, highlighting also the lower acidity of this solid, but gave rise to new Raman features for H2WO4, HNbMoO6 and HNbWO6. Lewis and Brønsted acid sites could be discriminated from the perturbation of the inorganic layers and related to surface sites. Therefore, the characterization by Raman spectroscopy in conditions of liquid intercalation proves to efficiently evaluate layered materials. Single-atom catalysts have attracted wide attention recently because of their unique size quantum effect and superior atom utilization in CO2 reduction reaction (CO2RR). Here, ultrathin Ni and nitrogen-codoped carbon nanosheets (Ni-N-CNSs) were proposed by a facile in-situ pyrolytic strategy. The ultrathin porous structure of Ni-N-CNSs affords large surface area, rich mesoporous volume and vast uniformly dispersed Ni atoms. The optimized catalyst exhibits a high CO Faradaic efficiency of nearly 100%, partial current density of 121.4 mA mg-1, CO production rate of 37.7 μmol mg-1 min-1, and super durability. In addition, the first principles calculations and the Mulliken charge analyses reveal the Ni sites show high bonding force towards the CO2 molecules, which gives rise to the high activity and selectivity of Ni-N-CNSs in CO2RR. HYPOTHESIS Membrane filtration is a promising technology for the treatment of alkali/surfactant/polymer (ASP) flooding oilfield wastewater, which contains high concentration of salt, surfactant, polymer and crude oil. The interactions of key foulants may influence the degree of membrane fouling. By comparing flux decline and interfacial free energies, it should be possible to derive the foulants governing the interactions with the membrane. EXPERIMENTS Polytetrafluoroethylene microfiltration membrane was employed to treat eleven types of model solutions to understand the effect of the interactions of key foulants on membrane fouling. The extended Derjaguin-Landau-Verwey-Overbeek theory was used to quantify the foulant-membrane and foulant-foulant interaction energies. The cake models were implemented to analyze the fouling form. Fourier transform infrared spectroscopy, atomic force microscopy, and contact angle were used to study the surface properties of various membranes. FINDINGS Microfiltration experiments and thermodynamic analysis revealed that both ions and sodium dodecylbenzenesulfonate could mitigate membrane fouling caused by anionic polyacrylamide (APAM) and crude oil. Moreover, APAM would produce a "shielding effect" on crude oil fouling. In addition, complete pore blocking, which primarily occurred on the membrane surface and formed a fouling layer, was the dominant form of membrane fouling. Amine-functionalized graphitic carbon nitride (g-C3N4) decorated with Au nanoparticles (CN/Au) was prepared by N2 plasma treatment of g-C3N4 powders impregnated with HAuCl4·3H2O. see more Well-dispersed Au nanoparticles with a small particle size were deposited on g-C3N4 nanosheets. In addition, the amino group was introduced into the CN/Au system. Without the addition of cocatalyst and sacrificial agent, CN/Au exhibited enhanced photocatalytic activity for CO2 reduction under visible-light irradiation. CO and CH4 evolution rates of CN/Au reached 28.3 and 1.3 μmol·h-1·g-1, which were 7.6 and 2.6 times higher than those of pristine g-C3N4 (CN-0), respectively. The enhanced activity can be explained by these factors. (1) The introduced amino group improved the adsorption capacity of CN/Au for CO2; (2) the hot electrons generated by Au nanoparticles activated the surrounding electrons through energy transfer and caused local temperature to rise, increasing the efficiency of the photoreduction reaction of CO2; (3) the Schottky junction between Au and g-C3N4 promoted the migration of electrons from g-C3N4 to Au nanoparticles, suppressing the recombination of the carriers.
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