Oxidation of aromatic sulfides with molecular oxygen: Controllable synthesis of sulfoxides or sulfones

The recent development of selective oxidation of aromatic sulfides with molecular oxygen was highlighted. The sulfoxides and sulfones could be obtained by simply switching the reaction media, i.e., bis(2-butoxyethyl)ether (BBE) or poly(ethylene glycol)dimethyl ether (PEGDME). The application of the high-boiling-point polyether as an initiator and green media can eliminate the need of large quantities of additives and volatile solvents. This strategy represents an economic and eco-friendly method that could find potential applications.     

γ-Rays-induced synthesis of hydrogels of vinyl ethers with stimuli-sensitive behavior

γ-Radiation method was applied to synthesize novel water-soluble and water-swelling polymers. Vinyl ether of ethylene glycol (VEEG), vinyl butyl (VBE) and vinyl isobutyl (VIBE) ethers were used as monomers. The synthesis of VEEG–VBE and VEEG–VIBE copolymers was carried out in a wide range of feed composition and absorbed dose. It was found that the hydrophobic–hydrophilic balance of the copolymers could be delicately varied by the copolymer composition as well as by the chemical structure of the alkyl substitute in the hydrophobic moiety. The copolymers exhibit thermo-sensitive behavior in water solutions. The value of transition temperature is considerably decreased at a higher concentration of the hydrophobic component in the copolymer composition.     

Chlorine adsorption on Si(1 1 1) studied by optical methods

The adsorption process of chlorine on Si(1 1 1) has been studied by means of real time surface differential reflectance (SDR) spectroscopy and second harmonic generation (SHG). The structure observed at 3.6 eV in SDR spectra is attributed to transitions including Si–Cl antibonding states. However, the overall feature is due to the removal of the electronic states of the clean surface. Developments of adsorption on Si adatom dangling bonds and breaking of adatom back bonds are obtained from SDR spectra and second harmonic (SH) intensity. They are well fit by the solutions of the rate equations under the assumption of adsorption of atoms without migration, and the initial sticking probability on the dangling bonds and the initial breaking probability of the back bonds are determined. Dependence of the adsorption kinetics on the carrier concentration is briefly reported.     

Fractional non-axisymmetric consolidation of stratified cross-anisotropic visco-poroelastic media

This paper investigates the fractional non-axisymmetric consolidation of stratified cross-anisotropic visco-poroelastic media. Firstly, based on the Laplace–Hankel transform, the ordinary differential equations of cross-anisotropic poroelastic media are derived, which are extended to those of fractional visco-poroelastic media by introducing the fractional Merchant model and the elastic-viscoelastic correspondence principle. Then, the extended equations are solved by the extended precise integration method (PIM), and the proposed theory is compared with the results reported in the references. Finally, selected numerical examples are performed to investigate the effects of the order of fractional derivative, viscoelasticity, cross-anisotropy and stratification on the non-axisymmetric consolidation.     

Underpinning energetics of lithium bonding and stability in the Li–Pt–Sn system

Within the Li–Pt–Sn system, we examine the electronic structures and Li-binding of LiPtSn₂, Li₂PtSn and Li₃Pt₂Sn₃ with fluorite-related crystal structures. The structures with totally de-intercalated lithium keep the characteristics of the pristine ternary compound with a reduction of the volume. In Li₃Pt₂Sn₃ the binding energies of lithium belonging to three crystallographically inequivalent Wyckoff sites are different and point to distinct activities of de-intercalation concomitant with site-selective bonding magnitudes. The derived potentials are within the range of non-oxide binary and ternary lithium based compounds and indicate the possibility of at least partial delithiation.     

Universal crossover function and non-universal order-parameter profiles for critical adsorption

We present a crossover theory for critical adsorption in a semi-infinite system. The predictions are compared with Monte Carlo simulations for an Ising model with a surface and with experimental measurements for the adsorption of liquid SF₆ on graphite. In both cases we find good agreement with theory.     

Model experiments of the transient response to flooding of the box shaped barge

Coupling of the flooded water and ship motions was studied experimentally. Roll decay tests for one flooded compartment and transient abrupt flooding tests were performed for the box shaped barge model. The tests were conducted to obtain information on the flooding process for the development of numerical tools and to provide validation data. Quantitative values on the effect of flooded water on the roll damping were obtained. Flooded water behaves in a different manner in undivided and divided compartments. Flooded water in divided compartment increases roll damping significantly. In undivided compartment roll damping was high at low amount of flooded water. For higher amounts damping was of the same order as for the intact model. Initial flooding is a complex process where the ship and flooded water motions are coupled. Propagation of the flooding water inside the compartment, at a dam-break type abrupt flooding, was studied by tracking the surface of the flooded water. An image processing algorithm was used to obtain the tracked surface. Flooded water volume and its center of gravity were estimated from the tracked surface. Different internal layouts of the flooded compartment can lead to a totally different roll response. The inflooding jet plays an important role in the response in case of the undivided compartment. While, for a divided compartment, asymmetric flooding due to the obstructions causes high heel angle on the damage side.     

Hydrodynamics in a new liquid–solid circulating conventional fluidized bed

A new type of liquid–solid fluidized bed, named circulating conventional fluidized bed (CCFB) which operates below particle terminal velocity was proposed and experimentally studied. The hydrodynamic behavior was systematically studied in a liquid–solid CCFB of 0.032 m I.D. and 4.5 m in height with five different types of particles. Liquid–solid fluidization with external particle circulation was experimentally realized below the particle terminal velocity. The axial distribution of local solids holdup was obtained and found to be fairly uniform in a wide range of liquid velocities and solids circulation rates. The average solids holdup is found to be significantly increased compared with conventional fluidization at similar conditions. The effect of particle properties and operating conditions on bed behavior was investigated as well. Results show that particles with higher terminal velocity have higher average solids holdup.