Quantitative effects of synthesis conditions on oil absorptive properties of oil gels based on EPDM/4‐tert‐Butylstyrene

The oil absorption properties of porous polymeric gels are dependent on their synthesis conditions. In this work, we have investigated whether it is feasible to find a quantitative relationship between the synthesis conditions of porous poly(EDPM/4‐tert‐Butylstyrene) gels and their behavior in the kerosene absorption through a factorial design of experiments. For this purpose, a series of such oil gels have been synthesized in toluene with various divinylbenzene (DVB) and EPDM contents. The kerosene absorbency and kerosene‐absorption kinetics of oil gels were determined. Finally, empirical models correlating the synthesis conditions with the kerosene absorbency (Q_eq) and kerosene‐absorption kinetic constant (K) were calculated; it was observed that lower the DVB concentration and higher the EPDM fraction in the monomeric mixtures, the higher the kerosene absorbency. With regard to the kerosene‐absorption kinetics, the largest K value was achieved with the lowest DVB concentration and the highest EPDM fraction. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of thermoreactive polysiloxanes with cyclic fragments in the side chain

The synthesis of polysiloxanes with pendant unsaturated cyclic fragments have been successfully performed by hydrosilylation reactions of polymethylhydrosiloxane with 4‐vinyl‐1‐cyclohexene in the presence of platinum hydrochloric acid (0.1 M solution in THF), Karstedt's catalyst (Pt₂[(VinSiMe₂)₂O]₃) and platinum on the charcoal (5%). Reactions were carried out at various temperatures with different ratios of initial compounds. It was shown, that not all active ≡Si? H groups take part in the hydrosilylation reaction. Some kinetic parameters of reactions were studied. The synthesized oligomers were characterized by FTIR, ¹H, ¹³C, H,H‐COSY, and C,H‐correlation NMR spectroscopy. Calculations using the quantum‐chemical semi empirical AM1 method for modeling reactions between methyldimethoxysilane [Me(MeO)₂SiH] and 4‐vinyl‐1‐cyclohexene were performed to evaluate possible reaction paths. Synthesized oligomers were characterized by gel‐permeation chromatography, differential scanning calorimetric, thermogravimetric, and wide‐angle X‐ray analyses. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Structural development Of TMMA and SSQXN‐8 as porous chelating resins

Superfast kinetics of Nd⁺³, Eu⁺³, and Gd⁺³ ions were studied on the surfaces of N,N,N^\,N^\‐tetramethylmalonamide (TMMA) and silsesquioxane (SSQXN‐8) resins. TMMA and SSQXN‐8 were prepared by suspension polymerization and sol–gel routes, respectively. They were identified using elemental analysis, FTIR, H‐NMR, ¹³C‐NMR, MIP, and BET surface area. Kinetic investigations were performed in batch conditions and different models were used to fit the data; Boyd and Helfferich models were found the best. The diffusion of the ions through the resins were very fast and found to be in the order of 10^?16 m²/S. Effective diffusions of the studied ions were found to be 10^?15 order of magnitude and directly proportional to the kinetic energy of the transition state. ΔS* values from ?166.044 to ?179.297 J mol^?1 K^?1 were estimated as entropy stability factors of the system. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

In situ activated 3,5-dinitrobenzoic acid covalent attached to nanostructured platform for NADH electrooxidation

The activation of 3,5-dinitrobenzoic acid (3,5-DNBA) in situ is proposed for electrocatalytic detection of NADH at low overpotentials. Thus, 3,5-DNBA was strategically connected to a nanostructured surface based on MWCNTs and PEI (an amine rich polymer). Then, R–NO/R–NHOH was electrogenerated in situ by cycling the potential between 0.15 and −0.55 V versus SCE. The formation of an intermediate charge transfer complex is proposed for the reaction between NADH and redox mediator. The apparent Michaelis–Menten constant (K_M) obtained by RDE voltammetry and amperometry was in good agreement, around 10⁻⁵ mol L⁻¹. The k_obs for the catalytic reaction evaluated by chronoamperometry and RDE voltammetry, was in good agreement and was found to be around 10⁴ L mol⁻¹ s⁻¹. The sensor provides a linear response range for NADH from 4.0 up to 42.0 μmol L⁻¹ with a sensitivity of 71 nA L μmol⁻¹, detection and quantification limits of 1.2 and 4.0 μmol L⁻¹ respectively, with a response time of 0.16 s.     

Coherence Analysis of Boiling Water Reactor Noise

Empirical studies of coherences between measurement variables from the operating data of a commercial nuclear power station of 460 MWe are applied to derive dynamical characteristics of the Boiling Water Reactor and to attempt to identify the noise sources of the neutron flux. Multivariate techniques with the partial coherence function and the multiple coherence function are introduced to eliminate correlated effects among measurement variables due to thermal hydraulic coupling and sophisticated reactivity feedbacks. From the results, the usual coherency (the ordinary coherence function) may not be adequate to estimate linear relations between measurement variables of the BWR. Furthermore, the noise sources of the neutron flux is discussed.     

DRYING OF POWDERY MATERIALS IN A PULSED FLUID BED DRYER

ABSTRACT

Drying of recycled polypropylene powder was studied experimentally in a laboratory pulsed fluid bed dryer (PFB) with relocated air stream. It was proved that fluidization of fine particles having a large specific surface area and a broad size distribution is technically feasible when using the composite supporting grid. Drying and hydrodynamic characteristics for a pulsed fluid bed of fine particles are found to be similar to the ones for coarse particles. Equations for minimum pulsed fluidization velocity, pressure drop, and surface and volumetric heat transfer coefficients are given.     

An efficient time scale model with tabulation of chemical equilibrium

The laminar and turbulent characteristic time-scale combustion model is extended for general reactive flows. In this model, energy and species compositions relax toward their corresponding local chemical equilibrium state over a characteristic time. Chemical equilibrium is efficiently evaluated using in situ adaptive tabulation (ISAT). The model is applied to a steady-state simulation of Sandia Flame D. The model is useful for simulations where kinetic mechanisms are not available, and also to provide good initial conditions for calculations with full chemical kinetics.