Argon plasma transport properties at reduced pressures

Argon plasma transport properties at low pressures (0.01 atm) are calculated using a modified Debve length suggested by T. Kihara et al. Electrons and heavy species are treated as two different gases, and the method of calculation is based on the simplified theory (or transport properties developed by R. S. Devoto. A generalized Saha equation is used to calculate the species composition, and experimental data by Y. Itikawa for momentum transfer cross sections are adapted for the evaluation of electron-atom collision cross sections.     

Effects of contact geometry on pull-off force measurements with a colloidal probe

This paper examines the effects of contact geometry on the pull-off (adhesion) force between a glass sphere (colloidal probe) and a silicon wafer in an environment with controlled relative humidity. An atomic force microscope is used to measure the pull-off force between the colloidal probe and the sample mounted at different tilt angles. The results show that the measured pull-off force is very sensitive to the tilt angle. Through the use of a newly developed direct scanning method, the exact contact geometry is determined for the zero-tilt angle case. The obtained digital image is then rotated to determine the contact geometry for the cases with other tilt angles. A detailed examination of the contact geometry, along with a magnitude analysis of the capillary force, suggests that the adhesion is most likely dominated by the capillary force from the meniscus formed between the probe and the sample. The strong dependence of the adhesion on the tilt angle may result from the change of meniscus dimensions associated with the probe-sample separation, which in turn is controlled by the highest peak on the probe sphere. Our observation emphasizes the combined role of microsurface shape near the contact and nanoroughness within the contact in determining the colloidal probe pull-off force and also microadhesion force in general.     

Characterization of Diesel Soot Particles Using Field-Flow Fractionation

Diesel engines have advantages over gasoline engines as they have higher thermal efficiency (thus producing less CO and hydrocarbons) and higher durability. Despite these merits, heavy-duty diesel engines are regarded as one of major sources of air-polluting particulate matters (soot) which are mainly fine carbonaceous particles. Environmental effects of diesel soot depend on the size and size distribution of the soot particles.     

Effects of Cr doping on structural and electrochemical properties of Li4Ti5O12 nanostructure for sodium-ion battery anode

Sodium-ion batteries are considered as promising alternatives to lithium-ion batteries,owing to their low cost and abundant raw materials.Among the several cand...     

Synthesis and Characterization of Nonlinear Optical Polymers Containing Carbazole and Disperse Red Dye

Dye‐containing nonlinear optical (NLO) polymers were synthesized: (1) poly(3‐(2‐(3‐(2‐isocyanatopropan‐2‐yl)phenyl)‐2‐methylpropyl)‐4‐methyl‐1‐phenylpyrrolidine‐2,5‐dione), P[(DR1,Cz)MSt‐PMI], and (2) poly(9‐vinyl‐9H‐carbazole‐co‐disperse red 1), PAV[DR1‐Cz]. The synthesized NLO polymers were characterized by ¹H‐NMR, IR, and UV–VIS spectroscopy; differential scanning calorimetry (DSC); and thermogravimetric analysis (TGA). The electro‐optic (EO) coefficients (r₃₃) and their NLO properties were evaluated by simple reflection and the Maker fringe method. The EO coefficients of P[(DR1,Cz)MSt‐PMI] and PAV[DR1‐Cz] were measured at 632.8 nm to be 106 and 46.6 pm/V, respectively. The second harmonic generation (SHG) coefficient (d₃₃) of P[(DR1,Cz)MSt‐PMI] was measured to be 71.25 pm/V.     

Collision of two rotating Hayward black holes

We investigate the spin interaction and the gravitational radiation thermally allowed in a head-on collision of two rotating Hayward black holes. The Hayward black hole is a regular black hole in a modified Einstein equation, and hence it can be an appropriate model to describe the extent to which the regularity effect in the near-horizon region affects the interaction and the radiation. If one black hole is assumed to be considerably smaller than the other, the potential of the spin interaction can be analytically obtained and is dependent on the alignment of angular momenta of the black holes. For the collision of massive black holes, the gravitational radiation is numerically obtained as the upper bound by using the laws of thermodynamics. The effect of the Hayward black hole tends to increase the radiation energy, but we can limit the effect by comparing the radiation energy with the gravitational waves GW150914 and GW151226.     

Implementation of splitter-less SPLITT fractionation and its application to large scale-fractionation of sea sediment

The split-flow thin cell fractionation (SF) is a useful tool for separating colloidal particles or macromolecules into two or more fractions in a preparative scale. In a conventional design, the SF channel is equipped with flow stream-splitters at the inlet and the outlet of the channel, which may cause deterioration of the resolution due to the disturbance in the flow stream by the imperfection of the splitter geometry. In this study, a new splitter-less SF channel was implemented, which was designed to operate only in the full-feed depletion (FFD) mode (FFD-SF). Without the splitters, it was possible to make the channel much larger than conventional ones (about 25 times larger in the channel volume), and thus obtain a much higher sample throughput (TP, amount of the sample that can be processed in a unit time period). The new splitter-less FFD-SF system was tested and optimized using polyurethane (PU) latex spheres, and then applied successfully to a large scale separation of sea sediment. A series of three steps of FFD-SF operations (with each step repeated, and there were 6 steps in total) yielded separation of the sea sediment into four fractions having diameter ranges of larger than 10 µm, between 5 and 10 µm, between 2 and 5 µm, and smaller than 2 µm. TP of the three FFD-SF operations were 37.3, 22.1, and 17.9 kg/h, and the fractionation efficiencies (FE) of the four size fractions were 80.5, 73.7, 79.1 and 86.1%. Results suggest the new splitter-less FFD-SF system could be a useful tool for large scale separation of complex particulates such as environmental particles.     

Separation and Characterization of Environmental Particulates Using Gravitational SPLITT Fractionation

Continuous SPLITT (Split-flow thin cell) Fractionation (CSF) is a preparative separation technique that is useful for fractionating particulates and macromolecular materials into two fractions. CSF is carried out in a thin ribbon-like channel equipped with two splitters at the channel inlet and outlet.     

Combination of gravitational SPLITT fractionation and field-flow fractionation for size-sorting and characterization of sea sediment

A combination of gravitational split-flow thin (SPLITT) fractionation and sedimentation/steric field-flow fractionation (Sd/StFFF) has been used for continuous size-sorting of a sediment sample and for size analysis of the collected fractions. An IAEA (International Atomic Energy Agency) sediment material was separated into four size fractions (with theoretical size ranges <1.0, 1.0–3.0, 3.0–5.0, and >5.0 m in diameter) by means of a three-step gravitational SPLITT fractionation (GSF) for which the same GSF channel was used throughout. The GSF fractions were collected and examined by optical microscopy (OM) and by Sd/St FFF. The mean diameters of the GSF fractions measured by OM were within the size interval predicted by GSF theory, despite the theory assuming that all particles are spherical, which is not true for the sediment particles. The Sd/St FFF results showed that retention shifted toward shorter elution time (or larger size) than expected, probably because of the shape effect. The results from GSF, OM, and Sd/StFFF are discussed in detail.