One-step synthesis,characterization and oxidative desulfurization of 12-tungstophosphoric heteropolyanions immobilized on amino functionalized SBA-15

Keggin-type 12-tungstophosphoric [PW₁₂O₄₀]^3? heteropolyanions were successfully immobilized onto mesoporous material surface of SBA-15 functionalized using the (3-aminopropyl)triethoxysilane (APTES) synthesized by one-pot co-condensation method, also called one-step synthesis. The synthesized PW^?-NH₃⁺-SBA-15 catalyst was characterized by XRD, N₂ adsorption–desorption, FT-IR, TGA, SEM, TEM, EDS, XPS methods. The results indicated that ordered hexagonal mesostructure for SBA-15 support was still maintained after being functionalized with amine groups, while the specific surface area of SBA-15 was decreased. The active species of phosphotungstic acid H₃PW₁₂O₄₀ (HPW) retained its Keggin structure of the heteropolyanions on the amine-modified SBA-15. The PW^?–⁺H₃N–SBA–15 catalyst exhibited a high catalytic activity for oxidative desulfurization process of sulfur-containing model fuel. The dibenzothiophene (DBT) conversion of almost 100% was achieved with reaction conditions of 40?mg of catalyst dosage, 2?mL of hydrogen peroxide, 90?°C of reaction temperature, and 120?min of reaction time.     

Analysis of polyaromatics in crude gas oil mixtures: a new strategy using H 2D n.m.r.

A new method for analysing complex mixtures, ¹H 2D n.m.r., was used to determine polyaromatics in crude gas oil mixtures. 2D NMR overcomes the lack of resolution due to crowded 1D spectra and provides structural information. In particular, TOCSY (total correlation spectroscopy) 2D n.m.r. is well suited to polyaromatics because these molecules give specific 2D fingerprints which can be easily recognized. These patterns were selected and analysed in two ways: (1) specific fingerprint recognition using a pure compound library; (2) using the mixing time τ_m of the TOCSY sequence. Variation of τ_m gives a change in cross-peak intensities. The intensity variation curves are characteristic of spin systems and hence of the structures of compounds. Alkylated substitutions were also studied. The compounds were quantified. This strategy was used to analyse crude gas oils and measure the contents of separated alkylated naphthalene isomers, biphenyls, anthracene, phenanthrene and benzothiophene.     

Serum cytokine levels in heart allograft recipients: correlation with findings on endomyocardial biopsy

We report the first double-blind, placebo-controlled continuation study comparison of a neuroleptic (haloperidol < or = 6 mg), monoamine oxidase inhibitor (MAOI) antidepressant (phenelzine < or = 90 mg), and placebo in 54 patients with borderline personality disorder. Continuation medication trials of 16 weeks followed 5 weeks of acute therapy. Haloperidol continued to be effective beyond the acute phase only for the treatment of irritability. Higher levels of depression, hypersomnia, and leaden paralysis were noted in the haloperidol group than in the phenelzine and placebo groups. The dropout rate during the first half (8 weeks) of the continuation study was significantly higher for the haloperidol group (64%) than for the placebo group (28%) (p < .05). Phenelzine demonstrated very modest efficacy beyond that noted in the acute phase for the treatment of depression and irritability. Phenelzine was shown to have an activating effect on measures of excitement and reactivity.     

Joint Optimization of Capacity and Flow Assignment in a Packet-Switched Communications Network

This paper presents a global optimal solution technique for the joint optimization of link capacity and flow assignment (CFA) in a packet-switched communications network,m-M/M/1queueing systems to model existing networks are considered. A continuous lower bound of the average packet delay is used in the formulation of the cost objective function for the capacity and flow assignment. The cost objective function thus formulated is shown to be convex with respect to the network multicommodity flow. This convexity ensures the global optimal solution to the CFA problem via the flow deviation (FD) method. Refinement of the CFA optimization techhique to allow optimal discretization of the continuous solutions to discrete solutions is presented based on dynamic programming and iterations of Flow Optimization and Capacity Optimization. Application examples of these optimization procedures are illustrated.     

Noncovalent functionalization of carbon nanotubes with amphiphilic gd3+ chelates: toward powerful t1 and t2 MRI contrast agents

An amphiphilic gadolinium (III) chelate (GdL) was synthesized from commercially available stearic acid. Aqueous solutions of the complex at different concentrations (from 1 mM to 1 microM) were prepared and adsorbed on multiwalled carbon nanotubes. The resulting suspensions were stable for several days and have been characterized with regard to magnetic resonance imaging (MRI) contrast agent applications. Longitudinal water proton relaxivities, r1, have been measured at 20, 300, and 500 MHz. The r1 values show a strong dependence on the GdL concentration, particularly at low field. The relaxivities decrease with increasing field as it is predicted by the Solomon-Bloembergen-Morgan theory. Transverse water proton relaxation times, T2, have also been measured and are practically independent of both the frequency and the GdL concentration. An in vivo feasibility MRI study has been performed at 300 MHz in mice. A negative contrast could be well observed after injection of a suspension of functionalized nanotubes into the muscle of the leg of the mouse.     

Red-emitting α-SrO·3B2O3:Sm2+ phosphor: an innovative application for increasing color quality and luminous flux of remote phosphor white LEDs

Abstract

By adding red-emitting α-SrO·3B₂O₃:Sm²⁺ phosphor and SiO₂ co-doping particles to yellow-emitting YAG:Ce phosphor compound, a novel method for improving lighting performance of white LEDs with remote phosphor structure, which have an average correlated color temperature (CCT) of 5600–8500 K, is proposed and demonstrated. By varying α-SrO·3B₂O₃:Sm²⁺ concentration from 2 to 30% and maintaining 5% SiO₂, the obtained results indicated that color rendering index (CRI), color quality scale (CQS), and luminous flux can be increased significantly. Moreover, the Mie-scattering theory is employed to verify the scattering properties, which have an effect on the enhancement of color quality and luminous flux. The results prove a prospective practical solution for manufacturing remote phosphor white LED (RP-WLED) having higher color quality and luminous flux.     

An investigation into surface modification of polyethylene films for hydrophilicity enhancement by catalytic ozonation

For a conventional polyethylene film, ozonation was conducted to increase its surface hydrophilicity. Copper sulfate was found effective as a catalyst in aqueous ozonation to increase the generation of surface peroxides significantly, which is the essential step for hydrophilicity enhancement. The percentage increase in peroxide generation could range from 41% to 58% by aqueous catalytic ozonation over its noncatalyzed gaseous counterpart. The optimum concentration of copper sulfate was found to be 0.05 g/L. After adding the catalyst, the length of ozonation could be significantly reduced so that the bulk mechanical strength of the films, represented by tensile strength, could be well preserved after ozonation. A novel kinetic model for the aqueous ozonation was proposed. This model was developed by combing the reaction mechanism of gaseous ozonation of polyethylene films with that of ozone self‐decomposition in water. The peroxide generation also increased with the applied ozone dose. The surface morphology and contact angle of the film were all examined before and after ozonation. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Application of mesoscale ensemble forecast method for prediction of wind speed ramps

Sudden changes in wind speed, so‐called wind speed ramps, are a major concern for wind power system operators. The present study applies the mesoscale ensemble forecast method for the prediction of wind speed ramps at wind farms in Japan and evaluates the ability and utility of this method. The mesoscale ensemble forecast in this study (ENS21) consists of 21 members with a horizontal resolution of 10 km for a 5‐year period. The simulated results show that ENS21 produces better accuracy than the deterministic forecast with a horizontal resolution of 10 km (DET_L). On the other hand, the deterministic forecast with a horizontal resolution of 5 km (DET_H) also produces better accuracy than DET_L. From a practical perspective, however, the ENS21 is computationally expensive. Thus, the eight‐member mesoscale ensemble forecast (ENS8) with as same computational cost as a deterministic forecast with a horizontal resolution of 5 km (DET_H) is also evaluated. The simulated results show that ENS8 has almost same accuracy as ENS21 and DET_H in wind speed ramp forecasts. ENS8 has advantages over ENS21 and DET_H because ENS8 is computationally efficient and is able to benefit wind power operators with flexibility in the selection of probability thresholds for decision processes compared with a single. It can be concluded that the mesoscale ensemble forecast method is more useful for prediction of the wind speed ramp than the single deterministic forecast method with the same computational cost if the ensemble members are successfully selected.