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Graphical abstract Highlights • Structured Pd supported on carbon nanotube modified nickel foam (CNTs@NF) was employed in the hydrogenation of polystyrene. • Pd nanoparticles highly dispersed on CNTs@NF surface displayed an excellent hydrogenation degree of PS. • CNTs@NF formed an inverse structure of traditional porous support and provided open accessible surface. • Enhanced mass transfer and abundant effective active sites contributed to the high performance of Pd/CNTs@NF. • Pd/CNTs@NF showed similar activity as slurry CNTs supported catalyst (Pd/CNTs) with the merit of avoiding filtration. Abstract A structured support of carbon nanotubes modified nickel foam (CNTs@NF) was synthesized through a facile method of chemical vapor deposition. The entangled CNTs layer with open pores and the dense carbon layer beneath covered around the skeleton of nickel foam establishes a hybrid hierarchical structure with large effective surface area which dramatically promotes the internal diffusion of large polystyrene (PS) coils. Palladium was chosen as the catalyst for PS hydrogenation and deposited on the CNTs@NF support in the form of nanoparticles. Characterization analysis including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermo gravimetric analysis (TGA), Raman spectrum and N 2 physisorption were conducted to investigate the morphology and structure of the resulting Pd supported on CNTs@NF catalysts (Pd/CNTs@NF). The macroscopic structured Pd/CNTs@NF catalyst was applied to PS hydrogenation and displayed a quite excellent hydrogenation activity with a final hydrogenation degree (HD) of 73.6%, almost 8 times higher than nickel foam supported Pd catalyst (Pd/NF) and remarkably similar to powdered CNTs supported Pd catalyst (Pd/CNTs) under the identical condition. Moreover, the turn-over-frequency (TOF) of Pd/CNTs@NF (0.041 s−1) was also comparable to Pd/CNTs (0.056 s−1), which confirmed a similar intrinsic catalytic activity of Pd on both supports. Inspiringly, the performance of Pd/CNTs@NF catalyst was comparable to powdered Pd/CNTs catalyst with the merit of eliminating filtration operation. It has revealed the structured Pd/CNTs@NF catalyst with outstanding recyclability could be an attractive alternative to the powdered Pd/CNTs catalyst for heterogeneously catalyzed polymers hydrogenation reactions. [ABSTRACT FROM AUTHOR]

An unsteady hydro-magnetic flow of a viscoelastic fluid from a radiative vertical porous plate has been studied with mass transfer, taking the effect of Hall currents into account. The resulting problem has been solved analytically and the closed form solutions are obtained for velocity, temperature and concentration distributions as well as for the shearing stress, rate of heat and mass transfer at the wall. The influence of the various parameters like Hall parameter, magnetic parameter, viscoelastic parameter, frequency parameter etc. on the flow field is examined with the help of figures and tables.

The purpose of this article is to review the state of art of the existing approaches to the design and analysis of pulsed and reciprocating columns, compare the merits of the theoretical models vs. the experimental “black box” method, and try to recommend a way to obtain a fruitful cooperation between researchers using different approaches. There are three main theoretical approaches: models based on the correlation of single parameters (holdup, drop size, mass‐transfer coefficient etc.), drop population balances, and computational fluid dynamics (CFD). At present, the design of new columns is based only on experimental data from piloting, sometimes with the assistance of mass‐balance simulators. And the experimental “black box approach” has proven to be efficient and quick, especially since at present no company considers the erection of a new column without some experimental verification. In the long term powerful models may enable the solution of many solvent extraction problems with reliability that does not require experimental verification. In order to be widely useful, these models have to be transformed into user‐friendly simulators that require only easily available data as input. To achieve this, there must be close cooperation between the academic world and industry. Otherwise, they will simply remain academic exercises. And at the present state of knowledge, pilot‐plant testing remains an almost inevitable preliminary step to a full‐scale column design. [ABSTRACT FROM AUTHOR]

Carbon monoxide is produced in high concentrations by gasification of coal or biomass, and is a potentially inexpensive feedstock for biological processes. A number of anaerobic microorganisms metabolize carbon monoxide, with acetate, hydrogen, or methane being the primary reduced products. The CO strain of Butyribacterium methylotrophicum was previously shown to grow on carbon monoxide as the sole carbon and energy source, with acetate being the primary product. This paper demonstrates that by modifying culture conditions, the carbon and electron flow of B. methylotrophicum can be manipulated to yield butyrate as the major product. A butyrate concentration of 6 g/L was obtained in batch culture with continuous addition of 100% carbon monoxide. The significance of this fermentation for fuels and chemicals production from carbon monoxide is discussed. [ABSTRACT FROM AUTHOR]

ABSTRACT Background: in Colombian the consumption of fresh green mango (also known as mango “biche”) is quite popular, and is consumed with lemon juice, salt, and honey. However, its high humidity content and high water activity makes of mango a highly perishable fruit, thus requiring processing alternatives. Osmotic dehydration (OD) is an interesting alternative for the conservation of mango. In OD, binary solutions (Solute + water) and ternary solutions (2 Solutes + water), have been traditionally used, however, more water removal can be achieved using ternary solutions, which leads to the improved organoleptic properties of dehydrated products Objetives: to evaluate the kinetic water loss (WL), solutes gain (SG), weight reduction (WR), water activity (a w ), and volume (Shrinking Coefficient, SC)) in green mango (Mangifera indica L. Filipino variety) osmotically dehydrated (OD). Additionally, to calculate water and solutes diffusivity (D ef ) for each treatment. Methods: green mango samples, with maturity scale zero, were used. Ternary solutions of sucrose at 40% and NaCl at 3, 6 and 9% were used for OD. The binary solution of sucrose with water as control treatment, was used. In the osmotic process samples were taken out at different times of OD (15, 30, 60, 90, 180, 240, and 300 min). Results: the findings show that at a higher concentration of NaCl, the dehydration kinetics was more rapid, a w and SC were smaller and, water and solutes D ef were higher. The samples dehydrated with the greatest solutes concentration (40 - 9%) reached the highest WL, SG, and WR with 89.52, 13.10, and 46.68%, respectively. Coefficients D efw and D efs showed a magnitude order of 10-10 m2/s, which is within the interval of dehydrated foods. Conclusions: this research showed that binary (sucrose + water) and ternary (NaCl + sucrose + water) solutions, are suitable for dehydrating green mango, however, the ternary solutions were more effective.

As for any other system used in wastewater treatment, it is important to know the mixing characteristics and net oxygen balance in high-rate algal ponds (HRAPs). The design of HRAPs obviously is conducive to plug flow, but with a large recirculation flow rate. The pond's treatment capacity will also depend on the net oxygen balance resulting from photosynthesis and respiration. In order to define an appropriate model describing the oxygen balance in the system, two techniques are respectively used for determining the hydrodynamic parameters and oxygen transfer coefficients of HRAPs. [ABSTRACT FROM AUTHOR]