Effect of magnetic lens on the electrospinning whipping instability, fiber diameter and its distribution

Electrospinning is an efficient and straightforward method for producing thin fibers from various materials. Although such thin fibers have diverse potential applications, the remaining problems with electrospinning are the whipping instability (also known as bending instability) of electrically charged liquid jets of polymer nanofibers and uneven fiber diameter distribution. In this study, we report a novel magnetic lens electrospinning system and discuss the principle of reducing the fiber diameter and width of the whipping circle in this electrospinning process. The effects of three types of electrospinning devices, needle-to-plate, needle-exciting coil-to-plate, and needle-magnetic lens-to-plate types, were studied through numerical simulation to analyze the electrospinning fiber collection state. For the 12 wt% polyacrylonitrile solution, when the applied voltage was 14–20 kV, the feed rate was 0.4–0.7 ml/h, and the current applied to the excitation coil or magnetic lens was 1 A, the experimental results demonstrated that, compared with needle-to-plate-type and needle-exciting coil-to-plate-type electrospinning, needle-magnetic lens-to-plate-type electrospinning produced smaller whipping circles with thinner and more uniform fibers.

Potential Application of Pin-to-Liquid Dielectric Barrier Discharge Structure in Decomposing Aqueous Phosphorus Compounds for Monitoring Water Quality

Here, we proposed a pin-to-liquid dielectric barrier discharge (DBD) structure that used a water-containing vessel body as a dielectric barrier for the stable and effective treatment of aqueous solutions in an open atmosphere. To obtain an intense pin-to-liquid alternating current discharge using a dielectric barrier, discharge characteristics, including the area and shape of a ground-plate-type electrode, were investigated after filling the vessel with equivalent amounts of water. Consequently, as the area of the ground electrode increased, the discharge current became stronger, and its timing became faster. Moreover, we proposed that the pin-to-liquid DBD reactor could be used to decompose phosphorus compounds in water in the form of phosphate as a promising pretreatment method for monitoring total phosphorus in water. The decomposition of phosphorus compounds using the pin-to-liquid DBD reactor demonstrated excellent performance—comparable to the thermochemical pretreatment method—which could be a standard pretreatment method for decomposing phosphorus compounds in water.

Stem anatomy of Apioideae (Apiaceae): effects of habit and reproductive strategy

Apioideae is the biggest and the most diverse of four subfamilies recognised within Apiaceae. Except for a few, likely derived, woody clades, most representatives of this subfamily are herbaceous. In the present study, we assessed stem anatomy of 87, mostly therophytic and hemicryptophytic, species from at least 20 distinct lineages of Apioideae, and juxtaposed them with 67 species from our previous anatomical projects also focused on this subfamily. Comparing our data with the literature, we found that wood anatomy does not allow for a distinction between apioids and their close relatives (Azorelloideae, Saniculoideae), but more distantly related Mackinlayoideae differ from Apioideae in their perforation plate type. Vessel element and fibre length, and vessel diameter were positively correlated with plant height: phenomena already reported in literature. Similar pattern was retrieved for vertical intervessel pit diameter. Wood ground tissue in apioids ranges from entirely fibrous to parenchymatous. The shortening of internodes seems to favour the formation of parenchymatic ground tissue, whereas the early shift to flowering promotes the deposition of fibrous wood in monocarpic species. These results support a hypothesis on interdependence among internode length, reproductive strategy, and wood ground tissue type.