One-pot, facile synthesis and fast separation of UiO-66 composite by metalloporphyrin using nanomagnetic materials for oxidation of olefins and allylic alcohols

One-pot facile synthesis of a new composite based on the incorporation of a metalloporphyrin within the UiO-66 metal-organic framework is reported. To enhance the catalytic activity of UiO-66, pore modification...

Fast engine noise sources separation based on short-time segmentation method

Cyclic Wiener filtering method (CWFM) has been widely used in engine noise sources separation but it is extremely time-consuming. In order to improve the efficiency, this paper proposes a fast separation method of engine noise sources based on the short-time segmentation method. In this method, signals from the acceleration condition are discretized into a large number of short-time signal segments to replace the steady-state conditions to separate engine noise sources at all speeds. The prerequisites for the short-time stationary assumption of the signal under acceleration condition are studied through experiments. The cylinder pressure-dependent noise (CPDN) separated by the fast separation method has been proven to have high precision through an experiment of accelerated condition under a load near zero. This method is used for noise sources separation of a diesel engine. It only needs to repeat the uniform acceleration several times for each load and the engine noise in all operating conditions can be separated into CPDN, load-dependent noise (LDN) and mechanical noise (MN). The result initially indicates the optimization direction of the engine noise. In addition, CWFM can be used to further separate the combustion noise in the operating conditions where the CPDN is prominent. The engine noise sources can be separated efficiently and accurately by maximizing the advantages of these two methods.

Methodology for Breaking Up Nanoparticle-Stabilized Oil/Water Emulsion

Summary A state-of-the-art portable dispersion characterization rig (P-DCR) is applied to study emulsions with Exxsol™ mineral oil (ExxonMobil Chemical Company, Houston, Texas, USA), commercial distilled water, and hydrophobic silica nanoparticles (NPs) as emulsifiers. The emulsion is prepared in the P-DCR batch-separator vessel, whereby the separation kinetics are observed and recorded. In this study, emulsion breakup by the integration of oil extraction/water addition and a stirring process is investigated, which is formed with 25% water cut (WC) and 0.01% w/w hydrophobic NPs (dispersed in the oil phase). The experimental data are divided into three data sets: oil extraction only, oil-extraction/pure-water addition, and oil-extraction/water with hydrophilic NP addition. For oil extraction only (Data Set 1), the WC of the fluid mixture increases, and for a sufficient volume extraction, phase inversion occurs that results in a complete separation of the oil and water. The minimum final required NP concentration for a fast separation, defined as the minimum concentration of NP required to begin the phase separation of the emulsion, is approximately 0.0045%. The acquired data for oil-extraction/pure-water-addition (Data Set 2) result in a faster breakup of the emulsion, as compared with oil extraction only. The oil-extraction/pure-water-addition process increases the system WC faster, reaching the phase-inversion point sooner. For the oil-extraction/pure-water-addition, the final lowest WC and NP concentrations are approximately 37% and 0.006% w/w, respectively, for fast separation. Thus, it can be concluded that the NP concentration and the WC are related. Repetitive oil-extraction/pure-water-addition cycles enable determination of the combined effects of the WC and NP on the separation process. A relatively stable emulsion is reached after approximately 2 minutes from the beginning of each cycle, which enables determining whether a quick separation occurs at the current cycle. Data Set 3 (oil-extraction/water with hydrophilic NP addition) results reveal that dispersing hydrophilic NPs in water does not promote emulsion breakup. On the contrary, the NPs produce a slightly more stable emulsion. The separation process, however, does not differ significantly even for high hydrophilic NP concentrations, emphasizing the dominant role of the hydrophobic particles (dispersed in the base-case emulsion).

A heterostructured PPy/ZnO layer assembled on a PAN nanofibrous membrane with robust visible-light-induced self-cleaning properties for highly efficient water purification with fast separation flux

A heterostructured PAN–PPy/ZnO nanofibrous membrane with superhydrophilicity/underwater superoleophobicity and regeneration capacity to efficiently and quickly remediate the complex oily sewage system.