Vetiver roots have been utilized for the preparation of activated carbon (AC) by chemical activation with different impregnation ratios of phosphoric acid, XP (g H3PO4/g precursor): 0.5:1; 1:1 and 1.5:1. Textural characterization, determined by nitrogen adsorption at 77 K shows that mixed microporous and mesoporous structures activated carbons (ACs) with high surface area (>1000 m2/g) and high pore volume (up to 1.19 cm3/g) can be obtained. The surface chemical properties of these ACs were investigated by X-ray photoelectron spectroscopy (XPS) and Boehm titration. Their textural and chemical characteristics were compared to those of an AC sample obtained by steam activation of vetiver roots. Classical molecules used for characterizing liquid phase adsorption, phenol and methylene blue (MB), were used. Adsorption kinetics of MB and phenol have been studied using commonly used kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the intraparticle diffusion model and as well the fractal, BWS (Brouers, Weron and Sotolongo) kinetic equation. The correlation coefficients (R2) and the normalized standard deviation Δq (%) were determined showing globally, that the recently derived fractal kinetic equation could best describe the adsorption kinetics for the adsorbates tested here, indicating a complex adsorption mechanism. The experimental adsorption isotherms of these molecules on the activated carbon were as well analysed using four isotherms: the classical Freundlich, Langmuir, Redlich–Peterson equations, but as well the newly published deformed Weibull Brouers–Sotolongo isotherm. The results obtained from the application of the equations show that the best fits were achieved with the Brouers–Sotolongo equation and with the Redlich–Peterson equation. Influence of surface functional groups towards MB adsorption is as well studied using various ACs prepared from vetiver roots and sugar cane bagasse. Opposite effects governing MB and phenol adsorption mechanism on ACs are demonstrated. The various effects involved in adsorption mechanisms of each molecule are demonstrated.

A series of water-soluble CdTe-core quantum dots (QDs) with diameters below 5.0 nm and functionalized at their surface with polar ligands such as thioglycolic acid (TGA) or the tripeptide glutathione (GSH) were synthesized and characterized by UV-vis absorption spectroscopy, their photoluminescence measurements, atomic force microscopy (AFM) and transmission electron microscopy (TEM). Because cell elongations and growth inhibitions were observed during labeling experiments, the cytotoxicity of CdTe-core QDs was investigated. Using growth inhibition tests combining different bacterial strains with different CdTe-core QDs, it was possible to demonstrate that the cytotoxicity of QDs towards bacteria depends on exposure concentrations, surface chemistry and coating, and that it varied with the strain considered. Growth inhibition tests carried out with heavy-metal-resistant bacteria, as well as ICP-AES analyses of cadmium species released by CdTe@TGA QDs, demonstrated that the leakage of Cd2+ is not the main source of QD toxicity. Our study suggests that QD cytotoxicity is rather due to the formation of TeO2 and probably the existence of CdO formed by surface oxidation. In this respect, QDs possessing a CdO shell appeared very toxic.

Lead(0) nano-/microcrystals with multiform crystal morphologies (separated nanoparticles, elongated nanoparticles, aggregated nanoparticles, polyhedral microcrystals and plate-like whiskers) were successfully synthesized by a facile and effective solution-phase method using lithium or sodium tert-butoxide-activated hydride as reducing and stabilizing agents. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy were used to characterize the samples. The experimental results indicated that the weaker t-BuOLi ligand was the more efficient for the growth/nucleation of spherical nanoparticles initially formed into larger particles. The possible mechanisms of Pb(0) microcrystals formation during ligand removal are presented. Additionally, we have investigated the magnetic properties and found that the nanoparticles exhibit a superconducting transition at 7.1±0.1K in agreement with the transition temperature measured in bulk Pb.

Adapting and combining specific biochemical and physical methods to investigate the properties of fat is the first step of an integrated approach conducted on fat-filled dairy powders, which have an economic and qualitative importance. The study includes the isolation, quantification and characterization of the free fat fraction, and the investigation of fat properties in situ in the powder. Free fat isolation is achieved by solvent extraction; the extracted fat can be quantified and further studied from thermal profile features by differential scanning calorimetry (DSC). Fat droplet sizes are investigated by laser light scattering: measurements are achieved on emulsions obtained after the rehydration of the powders. In situ methods mainly include investigation of the thermal properties by DSC, composition of the surface by X-ray photoelectron spectroscopy and qualitative observations by confocal laser scanning microscopy. After this study, reliable and connected methods are available (i) to quantify and locate the different types of fat within a powder particle and (ii) to investigate fat composition, structure and thermal properties. The need to combine several methods to conclude on a data set was demonstrated.

Stable Pd(0) nanoparticles were prepared at room temperature in 1,4-dioxane from PdCl2 using N,N′-bis(4-methoxyphenyl)-(1,1′-binaphthyl)-4,4′-diamine (naphthidine) as reducing and stabilizing agent. This procedure resulted in Pd(0) particles possessing an average diameter of ca. 25nm stabilized against aggregation due to a barrier of the naphthidine di(radical cation) Napht2.2+. These particles were evaluated for their capability to act as catalysts in Suzuki–Miyaura coupling reactions. The Pd(0)/Napht2.2+ provides a general and convenient method to prepare biaryls from aryl bromides or iodides and boronic acids with a broad range of functional groups in 1,4-dioxane at 80°C and under aerobic conditions.

A simple and direct Synthesis method was used to grow silicon carbide nanofibers in CH4/H-2, mixture on silicon substrates covered by Fe thin film catalyst using microwave plasma assisted chemical vapour deposition. The silicon source is the substrate itself. The samples have been characterized by field emission scanning electron microscopy and transmission electron microscopy combined with electron energy-dispersive X-ray spectroscopy. These characterizations revealed that fibrous nanostructures having stacking faults planes perpendicular to the growth direction coexist with fibrous with no stacking fault. These two types have a core-shell structure, with a diameter of 25-65 nrn, and were both assigned to beta-SiC. Selected area electron diffraction pattern shows that the faulted SiC structures exhibit streaks indicating defects (irregular layers) while the other ones have a single crystal pattern. One can also observe that the SiC nanofibers grow along (111) orientation. The formation of SiC nanofibers can be explained by the diffusion of Fe in the silicon substrate due to the high temperature during the process which is around 900 degrees C. The combination of the etching of the surface by atomic hydrogen and the interaction with carbon radicals and carbon atoms allows then the growth of SiC nanofibers. (c) 2008 Elsevier B.V. All rights reserved.

The influence of thioalkyl acid ligand was evaluated during aqueous synthesis at 100 degrees C and under hydrothermal conditions (150 degrees C) of CdTe and CdSe quantum dots (QDs). Experiments performed with 3-mercaptopropionic acid (MPA), 6-mercaptohexanoic acid (MHA) and 11-mercaptoundecanoic acid (MUA) demonstrated that the use of MHA and MUA allowed for the preparation of very small nanoparticles (0.6-2.5 nm) in carrying out the reaction under atmospheric pressure or in an autoclave and that the photophysical properties of QDs were dependent on the ligand and on the synthesis conditions. The influence of various experimental conditions, including the Te-to-Cd ratio, temperature, and precursor concentration, on the growth rate of CdTe or CdSe QDs has been systematically investigated. The fluorescence intensities of CdTe QDs capped with MPA, MHA, or MUA versus pH were also found to be related to the surface coverage of the nanoparticles.

This work presents a simple method to produce large quantities of crystallized antimony(0) nanoparticles through SbCl3 chemical reduction using t-BuONa-activated sodium hydride. t-BuONa acts as a superficial stabilizer of Sb(0) nanoparticles inhibiting their growth and avoiding aggregation. The Sb(0) nanoparticles were characterized using transmission electron microscopy, XPS analysis and X-ray powder diffraction. Results obtained show that rhombohedral Sb(0) with diameters of ca. 4.7±1.9nm were produced. The influence of purification conditions on the aggregation state of Sb(0) particles is also described.

The sorption of europium(III) species from EuCl3 solution at pH = 5.4 onto dickite particles is investigated using spectroscopic methods. Thanks to the neutrality of phyllosilicate sheets of dickite, cation exchange is prevented. X-ray photoelectron spectroscopy reveals that chloride atoms probably remain in the ligand sphere of the europium(III) cation. The edge site-specific reactivity is evidenced by epifluorescence microscopy and Raman spectroscopy. Comparison between dickite/europium(III) samples rinsed or not with distilled water shows that the surface processes not only involve inner-sphere complex formation, but also either outers-sphere complex or surface precipitation. Raman spectra also indicate that europium(III) surface complexes are preferentially localised at the edge of tetrahedral silica sheets.

Surface free energies of pine and beech wood were investigated before and after heat treatment using the Lifshitz–van der Waals/acid–base approach from contact angles measured by the Wilhelmy method. The results obtained showed that the decrease of the electron-donating component of the acid–base component was the major parameter affecting the wetting of the modified wood's surface. The Lifshitz–van der Waals component was slightly modified after heat treatment indicating that the atomic and molecular interactions due to permanent or induced dipoles between wood macromolecules were weakly modified. Modification of the surface chemical composition was studied by X-ray photoelectron spectroscopy (XPS) and titration of acidity. XPS indicated an important decrease of the O/C ratio after heat treatment explaining the decrease of the electron-donating component (γ−) of the surface free energy. The decarboxylation and degradation of glucuronic acids present in hemicelluloses, demonstrated by titration of carboxylic acid functions of wood, had only limited effect on the electron-accepting component (γ+).

The new Sb(0)/PANI nanocomposite was successfully synthesized by a one-pot solution phase method. Sb(0) particles were first prepared by the reduction of SbCl5 or SbCl3 using t-BuONa-activated NaH in THF. A ligand exchange with aniline on t-BuONa-stabilized Sb(0) particles yielded aniline-stabilized particles. The Sb(0)/PANI nanocomposite was finally obtained by polymerizing aniline-stabilized Sb(0) particles by using ammonium persulfate. The morphology and the structure of the nanocomposite was examined by transmission electron microscopy (TEM), selected-area electron diffraction (SAED), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Results obtained show that the Sb(0) precursor has a great influence on the size and the crystallinity of Sb(0) nanoparticles dispersed in PANI.

Monodisperse SnSb alloy nanoparticles were prepared by reduction of SnCl2 and SbCl5 using t-BuONa activated NaH. The morphology and the structure of the nano-alloy were examined by transmission electron microscopy (TEM), selected-area electron diffraction (SAED), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results showed that very small rhombohedral nanoparticles with an average diameter of 4.7±0.1 nm were produced. This route provides a promising candidate for studying capacities of nanosized SnSb alloys in electrochemical energy storage devices.

A novel route to prepare polyaniline (PANI)-supported Pd(0) nanoparticles by a one-pot chemical route is presented. Nanosized Pd(0) particles were first prepared by reduction of Pd(OAc)(2) using t-BuONa activated sodium hydride in refluxing THF. A ligand exchange with aniline on t-BuONa-stabilized Pd(0) particles yielded aniline-stabilized particles. Pd(0)/PANI nanocomposites were finally obtained by polymerizing aniline-stabilized Pd(0) particles using ammonium persulfate. Nanocomposites were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Results show that this one-pot experimental route is successful in producing hybrid materials constituted of Pd(0) nanoparticles stabilized by PANI due to the strong binding of PANI amine groups to Pd(0) particles. TEM images of the nanohybrids show that metal particles with diameters of ca. 4.9 nm are homogeneously dispersed in PANI. The preliminary results indicate that the Pd(0) particles supported on PANI behave as efficient heterogeneous catalysts in the Heck and Suzuki-Miyaura reactions of aryl iodides. Copyright (c) 2005 John Wiley & Sons, Ltd.

Development of simple and reliable protocols for the immobilization of catalytically active metal nanoparticles is an important aspect of the nanomaterials field. This paper describes the synthesis and characterization of new organic/inorganic hybrid materials constituted of Ni(0) nanoparticles and polyaniline (PANI). Nanosized Ni(0) particles were prepared by reduction of Ni(OAc)2 using t-BuONa activated sodium hydride in refluxing THF. A ligand exchange with aniline on t-BuONa-stabilized Ni(0) particles yielded aniline-stabilized particles. Ni(0)/PANI nanocomposites were finally obtained by polymerising aniline-stabilized Ni(0) particles by using ammonium persulfate. Samples were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Results show that this “one-pot” experimental route is successful in producing hybrids constituted of Ni(0) nanoparticles stabilized by PANI due to the strong binding of PANI amine groups to Ni(0) particles. TEM images of the nanohybrids show that metal particles with diameters of ca. 6 nm are homogeneously dispersed on PANI. The catalytic activity of these novel nanocomposites was finally evaluated in Heck reactions. The rate of coupling between aryl iodides and olefins using Ni/PANI catalysts was much higher than those obtained using Ni catalysts reported to date.

La gene est un des principaux effets negatifs du bruit. Elle represente une reaction psychologique globale dans laquelle un grand nombre de facteurs non-acoustiques interviennent, en particulier des facteurs d'attitude. Malgre les correlations relativement faibles, mais significatives, entre les niveaux d'exposition au bruit et la gene de long terme, on dispose actuellement de courbes dose-reponse assez fiables pour la population exposee au bruit routier et au bruit ferroviaire. Ces relations privilegient les indices energetiques (L Aeq et derives). Dans le cas de la gene instantanee, liee a un evenement sonore, les indices LAmax ou SEL sont plus appropries. A meme niveau d'exposition, la gene due au bruit ferroviaire est plus faible que celle due au bruit routier. Cet avantage pour le rail est tres souvent pris en compte dans les reglementations nationales a travers un terme correcteur appele egalement « bonus ferroviaire . Reste le cas plus complexe de la gene due a la presence de deux sources de bruit combinees (rail + route) qui necessite des travaux de recherche complementaires.

Valuing noise annoyance is almost always based on the willingness to pay concept. WTP sometimes reflects the awareness by individuals of noise effects, and sometimes, the amount of money that the community or individuals will agree to pay to reduce or prevent transportation noise annoyance. Among the valuation techniques used, hedonic price and contingent valuation methods are the most common. The hedonic price method is based on direct observation of consumer behaviour. Contingent valuation estimates the WTP of individuals to improve their noise environment in a hypothetical situation. The numerous results currently available are somewhat divergent but nevertheless demonstrate the importance of using noise values in transportation projects and policies.

Annoyance is one of the main negative effects of noise It represents an overall psychological reaction in which a great number of non-acoustic factors interfere, in particular attitudinal factors. In spite of relatively weak but significant, correlations between noise and annoyance, reliable dose-response curves are available for the community in which energetic indicators (Leq, LDEN) are prefered. However, these relations apply only to steady noise state situations and consequently are irrelevant for assessing the expected effects due to noise control. A more global environmental assessment (multinuisances) of the infrastructures would make it possible to better understand the expected attitude of the residents when implementing noise protection measures.

Tributyltin (TBT) is the most important organotin compound that has been introduced into aquatic ecosystems. A better understanding of its interactions with solid surfaces is essential to estimate the possibilities of TBT migration through subsurface environments. For this purpose, TBT sorption onto a porous matrix of natural origin, a quartz sand as an aquifer material, was studied at low concentration levels with a monodirectional model of column type allowing sequential investigation of sorption and desorption processes. Different treatments of the solid phase were performed by injecting alkaline solutions, NaOH at pH 10.8 or NaClO-NaCl at pH 11.5, by decreasing the ionic strength or by adding kaolinite to change the surface composition and properties. The removal of iron and aluminum (hydr)oxides from the sand surface did not affect so much the sorption (decrease in 14% as compared to sorption on the raw sand). The original use of X-ray photoelectron spectroscopy to control treatment efficiency and to characterize sand surface modifications permitted to relate TBT sorption onto the aquifer material to quartz, the main component of the sand, and clay minerals (mainly kaolinite) present at trace levels at the sand surface. A first attempt of transport modeling with these two surface sites showed the consistency of our assumption. Moreover, estimation of Langmuir-type constants showed that TBT sorption affinity for the quartz surface (KL = 26.7 L micromol(-1)) was much greater than for kaolinite (KL = 6.3 L micromol(-1)).

This paper gives a historic view of the use of monetary value of noise in cost-benefit analysis of large transport infrastructure projects in France over the last 5 years. Further to recommendations given in 1994 by the National Planning Oce, noise values are used by the National Road Administration since 1998 for new and modification of existing roads. A revision of the methodology as well as noise values are expected in 2000.

The BL/VL3 Kaplan radiation leukemia virus (RadLV-VL3) is a nondefective retrovirus that induces T cell lymphomas in several strains of mice. By using DNA probes derived from RadLV/VL3 provirus-flanking sequences cloned from the BL/VL3 cell line, we identified a DNA region rearranged in 5 of 19 tumors analysed (25%). All proviruses were integrated in the same 5′-to-3′ orientation in a small DNA region called Kis1 (Kaplan integration site 1). This region was localized on distal mouse chromosome 2 in a region not previously identified as important to lymphomagenesis. The cells rearranged at the Kis1 locus represent a clonal subpopulation of the clonal tumor masses examined, indicating a probable role of Kis1 in tumor progression.