Chemical Engineering

TiO 2 -Ag nanocomposites have been prepared by hydrothermal process for the preparation of photoelectrode for dye-sensitized solar cells. The formation of TiO 2 -Ag nanocomposites have been confirmed by the transmission electron microscopy (TEM), UV-Vis spectroscopy, X-ray diffraction and energy dispersive X-ray analysis. The TEM images confirm that silver nanoparticles of average size 30 nm are dispersed inside the TiO 2 matrix. Electrophoretic deposition technique (EPD) is successfully utilized to incorporate TiO 2 -Ag nanocomposites in commercially available TiO 2 nanoparticle to prepare photoelectrode on transparent oxide substrate. Incorporation of TiO 2 -Ag nanocomposites by EPD technique has been done in different ways: in all the layers of TiO 2 photoelectrode and in only the top layer of TiO 2 photoelectrode. X-ray diffraction, field effect scanning electron microscopy in back scattered mode and photoluminescence (PL) spectroscopy study confirm the presence of TiO 2 -Ag nan...

Qilei Song1,4, Shuai Cao2, Shan Jiang3, Andrew I. Cooper3, Anthony K. Cheetham2, and Easan Sivaniah1,5 Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK Department of Chemistry, University of Liverpool, Liverpool UK Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto 606-8501, Japan Email: q.song@imperial.ac.uk

A new strategy for controlling nonlinear parametrically dependent plants is proposed in order to ensure a good control performance and keep up the simplicity of Predictive Functional Control (PFC). Two alternative approaches are considered to realize a quasi linear PFC: manipulated variable blending and neighboring models blending. In this way it is avoided a nonlinear (NP) problem solving at each sampling time instant. Very simple no iterative calculations are needed. This implies that the computational load is slightly heavier in comparison with linear PFC (LPFC). The modified quasi-linear PFC algorithms are applied to a pH waste water neutralization laboratory stand. A comparative analysis is carried out between the proposed blending alternative approaches. Their performance is also compared with PFC and PID control schemes.

In the present work, we have used a facile chemical co-precipitation method to prepare porous (In, Mg) co-doped ZnO nanoparticles. X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electronic microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and UV-vis spectrophotometer characterizations were carried out for microstructural, morphological, and optical properties of samples studies. In-doping and (In, Mg) co-doping effect on the photocatalytic activities of ZnO was investigated. The results indicated that ZnO exhibits a high photo-degradation capability for OR-II under UV-light within 240 min. The degradation efficiency of OR-II after co-doping effect clearly demonstrates the excellent performance obtained with the powder particles made of 15 wt % Mg content. It showed an improvement in the photocatalytic activity by comparison to pure ZnO. In fact, the related sample shows that almost 90% degradation of OR-II occurred within 20 minutes. This remarkable catalytic performance opens the way for further exploration of the co-doped oxides in this application field.

By submitting this thesis electronically, I declare that the entirety of the work contained therein is my own, original work, that I am the sole author thereof (save to the extent explicitly otherwise stated), that reproduction and publication thereof by Stellenbosch University will not infringe any third party rights and that I have not previously in its entirety or in part submitted it for obtaining any qualification.

Cerium-manganese mixed oxides with different composition were prepared by co-precipitation, characterized and evaluated for the water-gas shift (WGS) reaction. Base metal (5 wt.% Cu and 5 wt.% Ni) catalysts supported on Ce-Mn mixed oxides were also tested for the WGS reaction. The activity of the bare supports is higher in the mixed samples than in pure ceria or manganese oxide. This result can be explained by a combination of greater reducibility and surface area in the mixed samples. Addition of base metals produces superior WGS catalysts. Particularly, nickel catalysts tested are able to reduce typical CO concentrations entering the WGS process to the CO levels tolerated by phosphoric acid fuel cells in a single unit operated at 400 °C.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

An efficient method to access 2-triazolyl thio-/selenopyridines with good to excellent yields by ruthenium(II)-catalyzed one-pot [3 + 2]/[2 + 2 + 2] cycloaddition reactions of azides, 1-alkynyl thio-/ selenocyanates and 1,6-diynes is reported. This atom-economical catalytic strategy offers a mild and practical approach to access a variety of such cycloadducts with good to excellect regioselectivities. The protocol was further extended to the synthesis of 3,3'-bis(triazolyl thio-/seleno)-2,2'-bipyridines by the reaction of tetraynes with 1-alkynyl thio-/selenocyanates in the presence of aryl/alkyl azides.

Al-doped ZnO (AZO) nanoparticles (NPs) have been synthesized via the thermal decomposition of metal acetylacetonate precursors in a nonoxygen and nonpolar solvent. Long-chain alkyl amines have been utilized to terminate the growth of AZO NPs and to stabilize them. The NPs have been characterized by a number of techniques as monocrystalline, exhibiting a hexagonal (wurtzite) structure with sizes from 8 to 13 nm. The composition of Al in the resulting NP is related solely to the composition of the reaction mixture and the size is controllable with the temperature of the reaction. The AZO NP dispersion has been proven to be stable over a 24 h period by dynamic light scattering measurements. The influence of the synthetic conditions, such as temperature, reaction time and the Al doping content, on the properties of NPs have also been investigated. An optically transparent AZO thin film was fabricated using the AZO nanoink by spin casting followed by annealing. The resulting film resisti...

A direct measurement of the pH of water in contact with supercritical COz was made by observing the spectra of a pH indicator with a W-vis spectrophotometer. The pH was analyzed under pressures of 70-200 atm and temperatures of 25-70 "C. The measured pH varied from 2.80 to 2.95, and relative standard deviations of ~1 . 5 % were achieved. The effects of pH on the efficiency of supercritical fluid extraction of metals and ionizable organic species in water-containing systems are discussed. Supercritical fluid extraction (SFE) has become an attractive alternative to conventional solvent extraction for the recovery of organic compounds and metal chelates from solid and aqueous samples.'sZ Carbon dioxide is the gas of choice for SFE because of its moderate critical constants, inertness, low cost, and availability in pure form. In many environmental applications, water is often present in an SFE system, either as a part of the original sample or added deliberately. The presence of water has been shown to facilitate the extraction of metal ions from solid materials using the in situ chelation technique in supercritical COz.2,3 The role of water in the SFE of organics and metals is not well understood. Water in contact with carbon dioxide becomes acidic due to the formation and dissociation of carbonic acid: Determining the pH of water in contact with supercritical COz is essential to understanding SFE of both metal ions and ionizable organic species. For SFE of metal ions, complexing agents are used to neutralize the metal charge and to transport the metals into the COS phase. The degree of dissociation of the complexing agents is dependent on the pH of the solution. If the complexing agents are not ionized at the solution pH, complexation and

This research aimed to use a low-cost, environmentally friendly adsorbent to eliminate the cationic dye Astrazon red 6B (AR) from an aqueous system. For this rationale, a nanocomposite hydrogel made of (Gum Acacia/Acrylamide)-calcinated Eggshell/Graphene oxide (GA/AAm)-ES/GO was created using Gamma radiation-induced copolymerization and cross-linking. FT-IR, XRD, EDX mapping, SEM, TGA and TEM were used to investigate the structures and properties. The nanocomposites exhibited superior adsorption behavior towards AR. Because of the dual effect of ES and GO, mixing ES with GO in (GA/AAm)-ES/GO nanocomposite hydrogel improved its adsorption capability. It was obtained that the optimum initial pH was 9 and the equilibrium contact time was 480 min. The removal percentage was enhanced by increasing the initial dye concentration. A little removal effectiveness was observed by increasing the adsorbent weight from 5.0 to 10.0 g for each liter of the dye solution. The Langmuir isotherm was fo...

A coupled analysis of the reaction kinetics and microstructural changes of Fe 2 O 3 /Al 2 O 3 oxygen carriers during redox reaction cycles for chemical looping systems was conducted. The microstructural changes in the oxygen carrier particles were investigated using an image analysis method with cross-sectional backscattered electron images, and microstructural information such as the particle size, porosity, and two-phase boundary between the iron oxide and pores was obtained. The microstructural changes and the degradation kinetics during redox cycles were investigated under various operating conditions (reaction temperatures, reduction times, oxygen partial pressures during the oxidation process, and weight ratios of the oxygen carriers). The degradation coefficient and the reaction enthalpy of the particles in the oxidation process are linearly related, implying that increasing the local temperature of the oxygen carriers causes the coarsening of iron oxide particles via sintering and microstructural changes. Our analysis contributes to the design of highly stable oxygen carrier particles and the improvement of the operating conditions for chemical looping systems.

A coupled analysis of the reaction kinetics and microstructural changes of Fe 2 O 3 /Al 2 O 3 oxygen carriers during redox reaction cycles for chemical looping systems was conducted. The microstructural changes in the oxygen carrier particles were investigated using an image analysis method with cross-sectional backscattered electron images, and microstructural information such as the particle size, porosity, and two-phase boundary between the iron oxide and pores was obtained. The microstructural changes and the degradation kinetics during redox cycles were investigated under various operating conditions (reaction temperatures, reduction times, oxygen partial pressures during the oxidation process, and weight ratios of the oxygen carriers). The degradation coefficient and the reaction enthalpy of the particles in the oxidation process are linearly related, implying that increasing the local temperature of the oxygen carriers causes the coarsening of iron oxide particles via sintering and microstructural changes. Our analysis contributes to the design of highly stable oxygen carrier particles and the improvement of the operating conditions for chemical looping systems.

Detailed analysis of bio-oil produced by hydrothermal liquefaction of marine micro algae. Detailed analysis of aqueous phase byproduct from hydrothermal liquefaction of marine micro algae. First application of FT-ICR MS to algal HTL bio-oils. ID of high MW nitrogen compounds and their distribution in HTL oil and aqueous phase byproduct.

The potential of using spent mushroom substrate (SMS) as inoculant carrier and organic amendment on the growth of Hibiscus sabdariffa was evaluated. SMS, peat and vermiculite were mixed with plant growth promoting bacteria (PGPB) isolate Bacillus amyloliquefaciens. Different treatments were applied in the cultivation of H. sabdariffa. We found that application of NPK fertilizer, SMS based inoculant, and peat based inoculant significantly promoted plant growth and chlorophyll content compared to other treatments. SMS based inoculant was the best treatment for increasing biomass and chlorophyll content, followed by NPK fertilizer. In addition, application of SMS inoculant or only SMS as soil amendment showed a significant improvement in soil properties including soil NPK, organic matter, soil PGPB and soil enzyme (i.e. soil fluorescein diacetate and dehydrogenase) as well as peat inoculant application. Our results suggested that SMS could be considered as an alternative low-cost, potential carrier in biofertilizer production or soil amendment for providing soil nutrients and recovering soil fertility in farming.

The potential of using spent mushroom substrate (SMS) as inoculant carrier and organic amendment on the growth of Hibiscus sabdariffa was evaluated. SMS, peat and vermiculite were mixed with plant growth promoting bacteria (PGPB) isolate Bacillus amyloliquefaciens. Different treatments were applied in the cultivation of H. sabdariffa. We found that application of NPK fertilizer, SMS based inoculant, and peat based inoculant significantly promoted plant growth and chlorophyll content compared to other treatments. SMS based inoculant was the best treatment for increasing biomass and chlorophyll content, followed by NPK fertilizer. In addition, application of SMS inoculant or only SMS as soil amendment showed a significant improvement in soil properties including soil NPK, organic matter, soil PGPB and soil enzyme (i.e. soil fluorescein diacetate and dehydrogenase) as well as peat inoculant application. Our results suggested that SMS could be considered as an alternative low-cost, potential carrier in biofertilizer production or soil amendment for providing soil nutrients and recovering soil fertility in farming.

The effect of membrane distillation process parameters on ethanol-water separation has been investigated using a comprehensive mathematical model. Three mass transfer solutions are considered in the model, namely: the exact solution of the Stefan-Maxwell equations developed by Krishna and Standart; the approximate solution of the Stefan-Maxwell equations suggested by Krishna and Wesselingh; and the binary Fickian solution. Temperature and concentration variation along the flow and diffusion paths are accounted for in the model. Though the exact and approximate solutions of the Stefan-Maxwell equations are coincident with each other, some differences are noticed between them and the Fickian-based solution. The difference between the three mass transfer-based solutions, as well as the process performance under several process parameters, are discussed.

Isobaric vapor-liquid equilibrium data at 705 ± 1 mm Hg for the systems water-pyridine and water-pyridine-CaCl 2 were obtained using the modified Othmer circulation still. The experimental data for the water-pyridine system exhibited an azeotropic point at a water composition of 75.0 mol% and a temperature of 92.60 • C. The isobaric salt-free binary data were compared with predicted vapor-liquid equilibrium (VLE) data using the UNIFAC model. Good agreement between the experimental and the predicted results was obtained, with a root-mean-square-deviation (RMSD) in predicted bubble-point temperature and predicted vapor-phase composition of 0.28 K and 0.007, respectively. In addition to that, the experimental data were correlated with the Wilson, the NRTL and the UNIQUAC models. The calculated VLE data using the parameters found by these models were in good agreement with the experimental results. The VLE of water-pyridine mixtures in the presence of calcium chloride at different concentrations was found to be dramatically different from that of the salt-free mixtures. Calcium chloride had showed a salting-out effect on water and could eliminate the azeotropic point of the system when used under saturated conditions. In addition, analysis of the data showed that the salt resulted in "splitting" the liquid mixtures into two different liquid phases.

Isobaric vapor-liquid equilibria of methyl tert-butyl ether (MTBE)-methanol, MTBE-methanol-calcium chloride, and MTBEmethanol-lithium chloride mixtures were measured at 93.57 kPa using a Malanowski equilibrium still which circulates both the vapor and liquid phases. The experimental results of the salt-free system showed that MTBE-methanol forms a minimum boiling azeotrope of 69.80 mol.-% MTBE at 93.57 kPa and 322.67 K. The experimental results of the salt-free system were predicted using the original UNIFAC and the UNIFAC-Dortmund methods, where the vapor-phase compositions were predicted with root-mean-square deviations (RMSD) of 0.0046 and 0.0091, respectively, and the bubble point temperatures were predicted with RMSD of 0.36 and 0.71 K, respectively. The Wilson and the nonrandom two-liquid (NRTL) models could satisfactorily correlate the experimental data of the salt-free mixtures with RMSD in the vapor-phase compositions calculation of 0.0047 and 0.0059, respectively and in bubble-point temperatures calculation of 0.20 and 0.40 K, respectively. Addition of either calcium chloride or lithium chloride to the MTBE-methanol mixtures resulted in salting-out the MTBE and shifting the azeotropic point to a vapor composition of 76.5 mol.-% and 93.0 mol.-% MTBE, respectively. Both the Tan-Wilson and Tan-NRTL models could satisfactorily predict the bubble-point temperatures of the MTBE-methanol-calcium chloride mixtures with RMSD of 0.143 and 0.130 K, respectively, and the vapor phase compositions with RMSD of 0.0055 and 0.0041, respectively.

The technical feasibility of using Jordanian low-grade phosphate (JLGP) for the removal of lead ions from aqueous solutions was investigated in this study. To simulate real industrial wastewaters, the effects of the presence of ethylenediaminetetraacetic acid (EDTA), citric acid, tartaric acid or sodium chloride on the adsorption of lead ions on JLGP were also investigated. The results of batch adsorption experiments demonstrated the high capability of JLGP for removing lead ions from aqueous solutions. The equilibrium data for the adsorption of lead ions onto JLGP could be fitted by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) isotherm equations. The work presented showed that on using 1 mmol/l of an aqueous solution of any of Pb(II), Pb-NaCl, Pb-tartaric acid, Pb-EDTA or Pb-citric acid, the percentage removal of lead ions at equilibrium was in the order Pb(II) > Pb-NaCl > Pbtartaric acid > Pb-citric acid > Pb-EDTA. Increasing the initial pH of the solution led to an enhancement in the sorption of lead ions and lead-ligand complexes onto JLGP. It was also found that increasing the concentration ratio of ligand to metal ion decreased the percentage removal of lead ions significantly. The sorption of lead ions from industrially simulated wastewater was found to follow pseudo-second-order kinetics.

Date pits, i.e. agricultural wastes, were converted into activated carbon by air and phosphoric acid activation. The surfaces of some of the prepared activated carbons were modified chemically using 8-hydroxyquinoline. The carbons prepared by both air and phosphoric acid activation showed surface areas of 864.8 m 2 /g and 502.2 m 2 /g, respectively, and micropore volumes of 0.298 cm 3 /g and 0.126 cm 3 /g, respectively. The adsorption of Methylene Blue onto the prepared activated carbon demonstrated its very high adsorption capacity. The adsorption of lead ions on both carbons, i.e. activated and chemically-modified, was studied under different conditions. The experimental results showed that both types of carbon gave a relatively large maximum lead ion uptake, the increase in the uptake as a result of chemical modification being insignificant. Lead ion uptake was found to increase by increasing the solution pH -whereby the maximum adsorption of lead ions was obtained at pH 5.2 -and by increasing the initial lead ion concentration. Equilibrium studies showed that the adsorption of lead ions on both adsorbents could be described by the Langmuir and Freundlich isotherm models. Kinetic studies showed that the adsorption of lead ions on the prepared activated carbons followed pseudo-second-order kinetics. The presence of EDTA, acetic acid or citric acid led to a significant decrease of lead ion uptake by the activated carbons.

The duplex stainless steels are materials, which present a better combination of mechanical properties and stress corrosion resistance than ferritic and/or austenitic stainless steels. However, in the processing of these materials, hot working is a critical step that leads in many cases to the generation of cracks and/or to an unacceptable surface finish. In the present work, it has been observed that severe localisation of plastic flow into superficial shear bands is the responsible for transversal cracking during hot rolling of duplex stainless steels. Torsion is a deformation mode involving pure shear and it has been found to be very useful in tackling the problem of damage formation in these materials under hot working. The effects of the strain, temperature and the strain rate on the damage formation in duplex stainless steels have been analysed in order to improve the hot workab ility of this material. Microstructural observations reveal that cracks mainly concentrate at the f...

A major barrier to the systematic improvement of biomimetic peptide-mediated strategies for the controlled growth of inorganic nanomaterials in environmentally benign conditions lies in the lack of clear conceptual connections between the sequence of the peptide and its surface binding affinity, with binding being facilitated by non-covalent interactions. Peptide conformation, both in the adsorbed and non-adsorbed state, is the key relationship that connects peptide-materials binding with peptide sequence. Here, we combine experimental peptide-titania binding characterization with state-of-the-art conformational sampling via molecular simulations to elucidate these structure/binding relationships for two very different titania-binding peptide sequences. The two sequences (Ti-1: QPYLFATDSLIK and Ti-2: GHTHYHAVRTQT) differ in their overall hydropathy, yet via quartz-crystal microbalance measurements and predictions from molecular simulations, we show these sequences both support very similar, strong titania-binding affinities. Our molecular simulations reveal that the two sequences exhibit profoundly different modes of surface binding, with Ti-1 acting as an entropically-driven binder while Ti-2 behaves as an enthalpically-driven binder. The integrated approach presented here provides a rational basis for peptide sequence engineering to achieve the in-situ growth and organization of titania nanostructures in aqueous media and for the design of sequences suitable for a range of technological applications that involve the interface between titania and biomolecules.

The aim of this study was to gain further insight into b-carotene thermal degradation in oils. Multiresponse modeling was applied to experimental highperformance liquid chromatography-diode array detection (HPLC-DAD) data (trans-, 13-cis-, and 9-cis-b-carotene concentrations) during the heat treatments (120-180 °C) of two b-carotene-enriched oils, i.e., palm olein and copra. The test of different reaction schemes showed that b-carotene isomerization reactions were dominant and reversible. The resulting cis isomers and trans-b-carotene simultaneously underwent oxidation and cleavage reactions at the same rate constant. From the kinetic analysis, it appeared that-contrary to oxidation and cleavage reactions-isomerization rate constants did not follow the Arrhenius law. However, the isomerization equilibrium constant increased with temperature, favoring isomer production, particularly 9-cis-b-carotene. Its production was shown to be concomitant with oxidation and cleavage reactions, indicating that 9-cis-b-carotene could be a good degradation indicator during oil storage or processing.

The impact of deep-fat frying on the micronutrient content of plantain (Musa AAB "barraganete") was evaluated during processing of plantain chips called "tostones." Water content, micronutrients (potassium, Lascorbic acid, α-carotene, β-carotene) content, and the temperature within the food were quantified during the course of frying. A nonisothermal kinetics analysis of the 1st-order reaction (micronutrient degradation) induced by deep-fat frying, particularly in terms of the spatial distribution of temperature, was proposed. The kinetic parameters (pre-exponential factor k 0, activation energy E a ) were identified by nonlinear optimization, minimizing the residual variance between the experimental and theoretical micronutrient content. Agreement between model and experimental values was checked. During 1st and 2nd frying, potassium was well retained while carotenoid contents decreased significantly. Moreover, L-ascorbic acid contents decreased significantly, just during 2nd frying. k 0 was identified as well as E a observed for L-ascorbic acid, α-carotene, and β-carotene as 68.4 to 71.5 , 79.6 to 84.9, and 85.9 to 88.6 kJ/mol, respectively. β-carotene appeared to be more heat-resistant than α-carotene and L-ascorbic acid. The behavior of the nutritional markers appears to be the consequence of the thermal and hydric histories of the crust and of the heart of the plantain disk related to heat transfer during preparation of the "tostones.

A rapid, easy to handle and low cost assay of ascorbic acid was developed, which consists in miniaturization on microplate of a redox reaction monitored spectrophotometrically, the signal being directly related to the concentration of ascorbic acid in the sample. This method was investigated in accordance with the prerogative of regulation covering food additives in terms of linear range/linearity, limits of detection and quantification, accuracy (including trueness and precision), robustness and selectivity. The application of the method was tested to determine ascorbic acid diffusivity in agar gel used as an aqueous food simulant. The diffusivity value obtained was 0.31 Â 10 À9 m 2 s À1 , with a confidence interval of 20% at 95% level. Accuracy of the assay and of the point's location on ascorbic acid profiles were examined by Monte-Carlo method to assess their influence on accuracy of diffusivity value obtained. Assay uncertainty was clearly demonstrated to be a critical parameter.

Protein kinases dedicated to the phosphorylation of SR proteins have been implicated in the processing and nuclear export of mRNAs. Here we demonstrate in Saccharomyces cerevisiae their participation in cation homeostasis. A null mutant of the single yeast SR protein kinase Sky1p is viable but exhibits increased tolerance to diverse toxic cations such as Na + , Li + , spermine, tetramethylammonium, hygromycin B and Mn 2 + . This pleiotropic phenotype correlates with reduced accumulation of cations, suggesting a decrease in membrane electrical potential. Genetic analysis and Rb + uptake measurements indicate that Sky1p modulates Trk1,2, the high-affinity K + uptake system of yeast and a major determinant of membrane potential.

The structural and optical modifications of polysulphone polymer under swift heavy ion (SHI) irradiation have been compared. Polysulphone films were irradiated with 45 MeV Li +3 ions and 120 MeV Ni +9 ions with fluence varying from 3×10 10 to 3×10 12 ions/cm 2 . Optical and structural modifications were characterized by UV-visible spectroscpy and X-ray diffraction (XRD) method. It is observed that optical absorption increases with increasing fluence and the absorption edge shifts towards the red end of the spectrum. The value of band gap shows a decreasing trend with increasing ion fluences of both the ions but a sharp decrease in band gap was observed in case of Ni ion. XRD analysis shows the decrease in peak intensity with increasing fluence.

Lanthanum perovskites were synthesized by malic acid complexation and different amounts of palladium were added by dry-wet impregnation. Measurements of methane conversion on fresh and SO 2 -treated perovskite catalysts were made between 25 and 500 • C. Methane conversion on fresh catalysts commenced at ∼300 • C, and the best activities were achieved with low loadings of palladium. The B-site metal combinations Mn 0.4 Fe 0.6 and Mn 0.6 Fe 0.4 showed better conversion activity than Mn 0.5 Fe 0.5 and Fe. All fresh perovskite catalysts except those with 10% Pd gave 100% conversion of methane at 500 • C. The resistance of 10% Pd perovskite catalysts to sulfur was generally better than that of catalysts with low Pd loadings. This was due to the high Pd coverage on the perovskite surface. Fresh and SO 2 -treated LaMn 0.4 Fe 0.6 O 3 perovskite catalysts promoted with 2 and 2.5% of palladium exhibited the highest activities for methane conversion.

Two types of catalytic washcoats with different properties can be present simultaneously in a monolith channel, e.g. the flat foils and the corrugated ones in metallic monolith can be individually coated with specific type of the washcoat. The model of such multiphase, differentiated NO x storage and reduction (NSR) catalytic monolith converter has been developed. The important reactions as are the oxidation of carbon monoxide, hydrocarbons and hydrogen, the reduction of nitrogen oxides (NO x ), the water gas shift and the steam reforming reactions, the NO/NO 2 transformation, and the oxygen and NO x storage are considered. Unknown kinetic parameters of the NSR are evaluated from transient experiments with the samples of two different types of NSR catalysts. The first catalyst is of the Pt-␥-Al 2 O 3 -CeO 2 type with alkali earth metals (e.g. barium) as NO x storage components (active at lower temperature). The second one is of the PtRh-␥-Al 2 O 3 -CeO 2 type with both alkali earth metals and alkali metals (e.g. potassium) as NO x storage components (active at higher temperature). Simulations of periodic lean/rich operation of the low-temperature, the high-temperature and the differentiated (combined) NSR converters are performed. The results of the computations agree well with the experimental data. The dependences of integral NO x conversion on the lengths of the lean and rich phases and on the temperature of the inlet gas are discussed. The efficiencies of the low-temperature, the high-temperature and the differentiated NSR converters are compared at different operating conditions.

The durability of four noble metal catalysts was investigated in solvent emission oxidation. Mono-and bimetallic catalysts (Pt, Pt-Pd) were supported on ␥-Al 2 O 3 -La or ␥-Al 2 O 3 -Ce washcoats and they were aged in industrial conditions for max. 25 months. The catalytic activities (lightoff experiments with methane and n-butyl acetate) were determined before and after the ageing to compare the behaviour of catalysts. Catalysts were also characterized by BET and chemisorption measurements as well as with XRD, FTIR and SEM. According to the results, all the catalysts showed excellent stability after the ageing periods and no significant reduction in the activities were observed in the oxidation of n-butyl acetate. However, a small reduction in the activity of the catalysts was observed in the case of methane oxidation, which is related rather to poisoning or fouling of the catalysts than to thermal deactivation. This observation was also supported by other catalyst characterization methods.

The kinetics of CO oxidation and NO reduction reactions over alumina and alumina-ceria supported Pt, Rh and bimetallic Pt/Rh catalysts coated on metallic monoliths were investigated using the step response technique at atmospheric pressure and at temperatures 30-350°C. The feed step change experiments from an inert flow to a flow of a reagent (O,, CO, NO and Hz) showed that the ceria promoted catalysts had higher adsorption capacities, higher reaction rates and promoting effects by preventing the inhibitory effects of reactants, than the alumina supported noble metal catalysts. The effect of ceria was explained with adsorbate spillover from the noble metal sites to ceria. The step change experiments CO/O, and O/CO also revealed the enhancing effect of ceria. The step change experiments NO/H, and Hz/NO gave nitrogen as a main reduction product and N,O as a by-product. Preadsorption of NO on the catalyst surface decreased the catalyst activity in the reduction of NO with H,. The CO oxidation transients were modeled with a mechanism which consisted of CO and 0, adsorption and a surface reaction step. The NO reduction experiments with H, revealed the role of N,O as a surface intermediate in the formation of N,. The formation of N-N bonding was assumed to take place prior to, partly prior to or totally following to the N-O bond breakage. High NO coverage favors N,O formation. Pt was shown to be more efficient than Rh for NO reduction by H,.

Juçara (Euterpe edulis Martius) is a palm tree widely distributed in the Atlantic Forest, which produces round fruits that recently gained worldwide attention, mainly for its resemblance to fruits of Euterpe oleracea and Euterpe precatoria Martius used to produce açaí. Juçara fruits stand out for their high nutritional value, which contain different kinds of nutrients, including fatty acids, protein, fibers, minerals and vitamins, and bioactive compounds such as anthocyanins, non-anthocyanin flavonoids and phenolic acids, which are associated with potent biological activities. The main objective of this work is to present the available compositional data regarding juçara fruits to produce a comprehensive source of recent information on important chemical constituents and the potential health benefits of these fruits in reference to the species E. oleracea and E. precatoria. In addition, information on botanical aspects, production chain and markets are presented.

Honeydew honey has differentiated chemical and physicochemical characteristics besides potential functional properties such as antimicrobial, anti-inflammatory and antioxidant. In this sense, the interest and consumption of this honey as a functional product by the food industry and consumers have increased. Honeydew honeys usually present dark color, a lower content of monosaccharides and higher values of pH, acidity, electric conductivity, proteins, minerals, phenolic compounds, and oligosaccharides compared to blossom honeys, which contribute to its outstanding biological activities. Consequently, contaminations and adulterations of this honey can occur and compromise the quality, safety and authenticity of honeydew honey. Thus, detailed knowledge of the composition and properties of honeydew honeys is of great importance, especially considering that honeydew honeys are still few studied and therefore underestimated. Therefore, in this review, the physicochemical characteristics, chemical and bioactive composition, functional and health-promoting properties of honeydew honey as well as contamination, adulteration and authenticity of this honey are summarized.

Honey is a product traditionally consumed due to its possible health benefits promoted by natural antioxidants. However, few studies have evaluated the effect of in vitro gastrointestinal digestion on these compounds in honeys. To improve the knowledge of this subject, the present study aimed to investigate the influence of simulated digestion on the stability of antioxidant capacity (FRAP, DPPH, and Folin-Ciocalteu assays), phenolic compounds (LC-ESI-MS/MS), and minerals (CE-DAD) in Mimosa scabrella Bentham honeydew honeys. The results show that the digestive system, mainly after duodenal digestion, significantly decreased the antioxidant capacity assessed by FRAP (410.3 ± 18.3 to 564.7 ± 8.4 µmol Fe +2 100 g -1 ), DPPH (30.1 ± 0.8 to 33.9 ± 1.4 mg

This study investigated the neuroprotective effect of juçara fruit extracts against glutamate-induced oxytosis in HT22 cells. Potential relationships between the extracts' polyphenolic composition and their protective/antioxidant capacities were also investigated. Experiments with the addition of either the crude methanolic extract or hexane, dichloromethane, ethyl acetate and butanol fractions 24 h before glutamate (pretreatment) and together with glutamate (co-treatment) were performed. At the concentration of 10 μg ml -1 , the hexane and dichloromethane fractions were able to protect cells, both in pretreatment and co-treatment. These fractions presented the highest number of quantified polyphenolics (24 and 21, respectively) although the total levels were 63-fold higher in the dichloromethane fraction. Syringaldehyde, vanillin and 4-aminobenzoic, cinnamic, salicylic and syringic acids were found only in these fractions. The dichloromethane fraction presented higher 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, while the butanol and ethyl acetate fractions showed higher ferric reducing antioxidant power. These results suggest juçara fruits extracts as promising for the reduction of the risk of neurodegenerative diseases.

Due to the increasing demand and interest of the consumers of bracatinga honeydew honey, it becomes important to know its characteristics in order to guarantee the quality of this dark honey. It is also necessary to investigate possible parameters that easily determine their differentiation from other honeys, thus guaranteeing their authenticity. Therefore, in the present study, the physicochemical characteristics and the reducing/scavenging proprieties of 16 bracatinga (Mimosa scabrella Bentham) honeydew honey samples and 25 blossom honey (different botanical origin) samples from Santa Catarina, Brazil, were investigated. Bracatinga honeydew honeys were defined by its high free acidity, electrical conductivity and reducing/scavenging capacity, and low glucose content.Still, these specific parameters allowed the differentiation between bracatinga honeydew honeys and blossom honeys, from the of principal component analysis, contributing to the differentiation of these honeys.

Allyloxy-pyridinium salts with various substituents on the allylic moiety are shown to be very efficient coinitiators in radical promoted cationic polymerization of cyclohexene oxide. Depending upon the radical initiator chosen, cationic polymerizations may be initiated by either heat or light. For the most part, the mechanism of initiation involves the addition of free radicals formed by the radical initiator, and a subsequent fragmentation of the energy-rich intermediate yielding initiating pyridinium type radical cations. In additionÈ fragmentation polymerization, the substituent at the allylic moiety does not sig-niÐcantly inÑuence the polymerization rate, thus implying that fragmentation is the rate determining step. In some cases, oxidation of the primarily formed free radicals contributes to the formation of initiating species. The salts under investigation are also able, to various extents, to initiate cationic polymerization upon external stimulation (heating or UV irradiation) without added radical initiators.

Over the past 50 years demand for plastics drastically increased worldwide resulting in plastic wastes causing serious environmental problems. The main market sector of european plastics industry is the packaging industry most of which is polyolefins and poly(ethythylene-terephtalate). Polymer blends based on waste resources can solve the issues of recycling. We have studied rheological and tensile properties of three types of PET/engineering thermoplastic blends (PET/PC, PET/PA and PET/ABS) produced with different processing techniques. Miscibility of components of blends is limited leading to weak mechanical properties such as low tensile strength and/or elongation at break. Due to that phenomenon compatibilizing additives are also required. As compatibilizing additives olefin-maleic-anhydride copolymer based additives have been used in our experiments. Structure of additives differed from each other both in ratio and length of carbon chains of compounds linked to maleic-anhydride groups . Blends have been studied with PET content ranging from 10 % to 90 %. As an outstanding result we have managed to achieve improving mechanical properties, for example almost 400 % growth was observed in elongation at break of extruded 80/20 PET/PA blends in the presence of 0.2 % compatibilizing additive compared to the sample without additive, meanwhile its strength has also improved.

Over the past 50 years demand for plastics drastically increased worldwide resulting in plastic wastes causing serious environmental problems. The main market sector of European plastics industry is the packaging industry most of which are polyolefins and poly(ethylene-terephtalate). In the EU, 29.1 million tonnes of plastic waste were collected in 2018, of which 32.5% was recycled, 42.6% was recovered for energy, and 24.9% was landfilled (Plastics-the Facts, 2019). Although landfilling of collected waste in the EU is steadily declining, there is still too much unused waste. Polymer blends based on waste resources can solve the issues of recycling. The main purpose of the research was to produce polymer blends from waste based PET that have appropriate mechanical properties and rheological behaviour as well in order to find application areas where product requirements are not strict. Blends containing waste based PET were extrusion moulded and calenderd producing extrusion strings a...

In the present investigation, non-edible toxic oils from marine macroalgae Caulerpa racemosa species, richly available in India and composed of high calorific value and high FFA, have been selected as a feedstock for the making of biodiesel. Initially, oil extraction was carried out from the macroalgae biomass with different types of solvent syst ems and extraction steps. The algal oil was extracted with a solvent system consisting of 1 % diethyl ether and 10 % methylene chloride in nhexane using ultrasonic pre-treatment technique. The algal oils were characterized by Gas Chromatography-Mass Spectrometry for composition analysis. The biodiesel was produced by transesterification method. The produced biodiesel was characterized and the conversion was calculated by Fourier-transform infrared spectroscopy (FTIR) analysis and Response Surface Methods. The fuel properties of obtained biodiesel were examined as per the American Standard Test Methods specifications in order to assess the potential of proposed biodiesel as an alternative fuel. Thus, marine macroalgae serve as a potential renewable raw-material for biodiesel production.

The findings, interpretations and conclusions expressed herein are those of the authors and do not necessarily reflect the views of the United Nations or its officials or Member States. The designation employed and the presentation of material on any map in this work do not imply the expression of any opinion whatsoever on the part of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This publication has been externally edited.

Silicon (Si) nanowires (NWs) grown on stainless-steel substrates by Cu-catalysed Chemical Vapour Deposition (CVD) have been prepared to be used as anodes in lithium-ion batteries. The use of NWs can overcome the problems related to the Si volume changes occurring during lithium alloying by reducing stress relaxation and preventing material fragmentation. Moreover, since the SiNWs are grown directly on the substrate, which also acts as a current collector, an excellent electrical contact is generated between the two materials without the necessity to use additional binders or conducting additives. The electrochemical performance of the SiNWs was tested in cells using lithium metal as the anode. A large irreversible capacity was observed during the first cycle and, to a lesser extent, during the second cycle. All the subsequent cycles showed good reversibility even if the coulombic efficiency did not exceed 95%, suggesting the formation of an unstable SEI film and a continuous decomposition of the electrolyte on the silicon surface. The absence of a stable SEI film was assumed responsible for a linear capacity fade observed upon cycling. On the other hand, the electrochemical characterization performed at different values of the charging current showed that SiNWs possess an exceptionally high rate capability.

This paper describes a method for the preparation of composite cathodes for lithium ion-batteries by using poly vinyl acetate (PVAc) as a binder. PVAc is a non-fluorinated water dispersible polymer commonly used in a large number of industrial applications. The main advantages for using of this polymer are related to its low cost and negligible toxicity. Furthermore, since the PVAc is water processable, its use allows to replace the organic solvent, employed to dissolve the fluorinated polymer normally used as a binder in lithium battery technology, with water. In such a way it is possible to decrease the hazardousness of the preparation process as well as the production costs of the electrodes. In the paper the preparation, characterization and electrochemical performance of a LiFePO 4 electrode based on PVAc as the binder is described. Furthermore, to assess the effect of the PVAc binder on the electrode properties, its performance is compared to that of a conventional electrode employing PVdF-HFP as a binder. 2014 Published by Elsevier Ltd.

The active packaging films based on corn starch and chitosan were prepared through mixing the starch solution and the chitosan solution (1:1) by casting. The aim of this work was to characterize and analyze the effects of the chitosan concentrations (0, 21, 41, 61 and 81wt% of starch) on physicochemical, mechanical and water vapor barrier properties as well as morphological characteristics of the corn starch/chitosan (CS/CH) films. Starch molecules and chitosan could interact through hydrogen bonding as confirmed from the shift of the main peaks to higher wavenumbers in FTIR and the reduction of crystallinity in XRD. Results showed that the incorporation of chitosan resulted in an increase in film solubility, total color differences, tensile strength and elongation at break and a decrease in Young's modulus and water vapor permeability (WVP). Elongation at break of the CS/CH films increased with increasing of chitosan concentration, and reached a maximum at 41 wt%, then declined...

The underutilized, edible green raw (whole) fruits of amra, Spondias pinnata K. (Anacardiaceae family) from the eastern region of India were investigated for their nutraceutical and therapeutic potential. A thorough nutritional characterization of this fruit demonstrated it as a source of energy (348 kcal/100 g DM), phenolic compounds, natural antioxidants and minerals. It is also a moderate source of ascorbic acid, malic acid, calcium, phosphorus and other nutrients. The phytochemical screening revealed 5.12 ± 0.32 mg 100 g -1 DM of alkaloids followed by saponins and tannins. All assays were carried out in three different solvent extracts of the fruit. Total phenolic, flavonoid and flavonol contents were obtained as 210 ± 1.89 mg GAE, 28.0 ± 0.91 mg CE and 9.97 ± 0.72 mg RE respectively in 100 mg mix solvent extract (MSE). Antioxidant activity of different extracts (as DPPH scavenging) ranged from 0.73 to 0.59 mg ml -1 as IC 50 value, ABTS with a trolox equivalent antioxidant concentration (TEAC) value as 0.68 to 0.83 and FRAP 5.97 to 7.93 mg TE 100 mg -1 extract. LC-MS/MS analysis revealed the presence of gallic acid, salicylic acid, chlorogenic acid, ellagic acid, p-coumaric acid, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, quercetin, catechin, myrecetin and rutin. The MSE showed the highest antimicrobial activity (against Listeria monocytogenes (MIC 1.8 mg ml -1 )) and α-amylase inhibition capacity (as IC 50 : 29.3 mg ml -1 extract). GC/MS screening showed the presence of vitamin E, furfural, phytosterol, campesterol and fatty acids. Analysis of volatile flavor showed isopropyl myristinate as a major compound followed by the other monoterpenes and sesquiterpenes. The current study explains the nutritional as well as medicinal utility of the fruit which is a rich source of minerals and antioxidants such as phenols and flavonoids.