The branching ratio for K−p → Λγ at rest

The reaction K^?p → Λγ, produced by K^? stopping in a liquid hydrogen target, has been studied using a NaI(Tl) gamma-ray spectrometer. The branching ratio is

$\text{K}{}^{\mathrm{?}}\text{p}\text{→Λγ}\text{K}{}^{\mathrm{?}}\text{p}\text{→}\text{anything}\text{=(2.8±0.8)×10}{}^{\mathrm{?3}}$

based on 1355 events assigned to this branch. This is in conflict with a previous experiment, but agrees with one of the two published calculations, when recent values for the coupling constants and scattering amplitudes are used.     

Multifractality and high energy multiparticle production

The multifractal behaviours of the various types of high energy collisions are analyzed using the normalized factorial moments which are calculated from the experimental data. Thef() curves for the various types of collision are constructed. The width of thef() curves seems to indicate roughly degree of intermittency or fluctuation of the data. The width of the curves also does not seem to be affected by the energy.     

Turbulence characterisation of a confined jet using PIV

The turbulence in the bulk free region of a confined jet is investigated using a simple video-based particle image velocimetry technique. The latter, which relies on the interlacing properties of video filming and simple particle tracking concepts, is suitable for less dense seeding levels and lower flow velocities. The results obtained for the turbulence intensity variation in the jet agree with known data from literature. Spatially resolved integral length scales are calculated, and a relation for Eulerian-type length scales is proposed.     

Current Development and Challenges of Mixed Matrix Membranes for CO2/CH4 Separation

In the early stage of membrane technology development in gas separation, utilization of polymeric membranes has gained attention due to their robustness and ease of fabrication. However, the performance of polymeric membranes is limited by the trade-off between permeability and selectivity. Meanwhile, inorganic membrane is capable to exhibit great enhancement in separation performance but unfortunately its fabrication process is hard and costly. Thus, development of mixed matrix membranes (MMMs) by incorporating inorganic fillers into the polymer matrix has become a potential alternative to overcome the limitations of polymeric and inorganic membranes in gas separation. Nevertheless, fabrication of defect-free MMMs with improved separation performance and without compromising the mechanical and thermal stability is extremely difficult and challenging. In the current review paper, various types of inorganic fillers for MMMs fabrication and recent reported efforts to tailor the underlying problems on MMMs fabrication were discussed. The future outlook to advance the performance of MMMs in gas separation especially for CO₂/CH₄ separation was highlighted.     

Propagation properties and M2 factors of a vortex Airy beam

We investigate the propagation properties and M² factor of a vortex Airy beam. The expression of M² factor as a function of the modulation parameters a_x and a_y is analytically obtained. The results indicate that the M² factor can achieve minimum M²=2.33 when a_x=a_y=1.026 for the m=1st order vortex Airy beam. For m=2, the M² factor can achieve minimum M²=7.53 when a_x=1.601 and a_y=0.529 (or a_y=1.601 and a_x=0.529). These results indicate that the far field divergence of the beam width in the sense of root-mean-square beam is related to modulation parameters a_x and a_y, and increases with increasing vortex order. Numerical calculations provide an intuitive physical picture for the effect of the modulation parameters on the propagation of the vortex Airy beam.     

CONTINUOUS ABSORPTION OF TOLUENE VAPOR BY MICELLAR SOLUTIONS AND THE RESULTING MICROEMULSIONS

ABSTRACT

Microemulsions consisting of AOT-H₂O-toluene-hexyl carbitol (HC) or butyl carbitol (BC) were investigated in relation to the relative vapor pressure of toluene (P/P_o). The microemulsions generally revealed high (P/P_o). The relatively lower (P/P_o) was only obtained from those containing 10% and 15% AOT at higher levels of HC and BC respectively. From the linear plot of (P/P_o) against the volume fraction of toluene, the transition from micellar solution to microemulsion was evident. This transition phenomenon was also observed in the continuous absorption of toluene vapor. It was concluded chat the microemulsions studied were not efficient in scrubbing toluene vapor, but they were much more effective than their respective micellar solutions.     

Purified oxygenand nitrogen-modified multi-walled carbon nanotubes as metal-free catalysts for selective olefin hydrogenation

Oxygen-and nitrogen-functionalized carbon nanotubes (OCNTs and NCNTs) were applied as metal-free catalysts in selective olefin hydrogenation. A series of NCNTs was synthesized by NH3 post-treatment of OCNTs. Temperature-programmed desorption, N2 physisorption, Raman spectroscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were employed to characterize the surface properties of OCNTs and NCNTs, aiming at a detailed analysis of the type and amount of oxygenand nitrogen-containing groups as well as surface defects. The gas-phase treatments applied for oxygen and nitrogen functionalization at elevated temperatures up to 600 C led to the increase of surface defects, but did not cause structural damages in the bulk. NCNTs showed a clearly higher activity than the pristine CNTs and OCNTs in the hydrogenation of 1,5-cyclooctadiene, and also the selectivity to cyclooctene was higher. The favorable catalytic properties are ascribed to the nitrogen-containing surface functional groups as well as surface defects related to nitrogen species. In contrast, oxygen-containing surface groups and the surface defects caused by oxygen species did not show clear contribution to the hydrogenation catalysis.     

Polymerization of water-in-oil microemulsions: Methyl methacrylate,acrylic acid,and sodium acrylamidostearate

Water-in-oil (w/o) microemulsions of methyl methacrylate (MMA), acrylic acid (AA), sodium acrylamidostearate (NaAAS), and water were investigated. MMA, AA, and NaAAS could be terpolymerized in these microemulsions. For a composition of 54% MMA, 34% AA, 2% NaAAS, and 10% H₂O, polymers of high molecular weights of about 1,000,000 were obtained between 3.5 to 24% polymer conversion. The system became a transparent gel when conversion exceeded 36%. Transparent solid terpolymer containing water up to 16% were also obtained after fully polymerizations of certain compositions.     

Solubility prediction of paracetamol in binary and ternary solvent mixtures using Jouyban-Acree model

The Jouyban-Acree model has been used to predict the solubility of paracetamol in water-ethanol-propylene glycol binary and ternary mixtures based on model constants computed using a minimum number of solubility data of the solute in water-ethanol, water-propylene glycol and ethanol-propylene glycol binary mixtures. Three data points from each binary solvent system and solubilities in neat solvents were used to calculate the binary interaction parameters of the model. Then the solubility at other binary solvent compositions as well as in a number of ternary solvents were predicted, and the mean percentage deviation (+/-S.D.) of predicted values from experimental solubilities was 7.4(+/-6.1)%.