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Scientific Papers in SCI

2013


Influence of the O2/CO ratio and the presence of H2O and CO2 in the feed-stream during the preferential oxidation of CO (PROX) over a CuOx/CeO2-coated microchannel reactor


Laguna, OH; Dominguez, MI; Oraa, S; Navajas, A; Arzamendi, G; Gandia, LM; Centeno, MA; Montes, M; Odriozola, JA
Catalysis Today, 203 (2013) 182-187

ABSTRACT

The catalytic performance of a CuOx/CeO2 powder catalyst and that of a microchannel reactor or microreactor (MR) coated with the same solid was determined and compared. The catalytic activity measurements were carried out with varying O2/CO molar ratios in the feed-stream. In addition, the influence of the presence of CO2 and H2O in the reaction mixture was studied. Some discrepancies were observed between the performances of the powder catalyst and the MR depending on the O2/CO ratio. The MR presented a very good performance with a superior selectivity for CO conversion. This behaviour was due to a more efficient heat removal in the case of the MR that inhibited the H2 oxidation reaction and the r-WGS. The isothermicity of the microreactor during the process was demonstrated through the monitoring of the MR inlet and outlet temperatures.

Concerning the presence of CO2 or H2O in the feed-stream, both compounds gave rise to a decrease of the CO conversion. The negative effect on the catalytic performance was more marked when both compounds were fed together, although the principal inhibitor effect was associated to the CO2. This seems to be related with the formation of stable carbonates at the catalyst surface.


March, 2013 | DOI: 10.1016/j.cattod.2012.04.021

Solvent-Controlled Synthesis and Luminescence Properties of Uniform Eu:YVO4 Nanophosphors with Different Morphologies


Nunez, N; Sabek, J; Garcia-Sevillano, J; Cantelar, E; Escudero, A; Ocañaa, M
European Journal of Inorganic Chemistry, 8 (2013) 1301-1309

ABSTRACT

A facile solvothermal route has been developed for the preparation of tetragonal europium-doped yttrium orthovanadate nanoparticles (Eu:YVO4) and is based on a homogeneous precipitation reaction at 120 °C from solutions of rare earth precursors (yttrium acetylacetonate and europium nitrate) and sodium orthovanadate in ethylene glycol or ethylene glycol/water mixtures. The nature of the solvent has a dramatic effect on the morphology and crystallinity of the resulting nanoparticles. Polycrystalline nanoellipsoids (130 × 60 nm) were obtained in pure ethylene glycol, whereas quasispherical nanoparticles (100 nm) with monocrystalline character precipitated in ethylene glycol/water (7:3 by volume) mixtures. To explain these different morphological and structural features, the mechanism of particles formation was investigated. The effects of the doping level on the luminescence properties (emission spectra and luminescence lifetime) were also evaluated to find the optimum nanophosphors. Finally, it is shown that the luminescent efficiency of the quasispherical nanoparticles was higher than that of the nanoellipsoids; this can be related to differences in crystallinity and in impurity content.


March, 2013 | DOI: 10.1002/ejic.201201016

Joining and interface characterization of in situ reinforced silicon nitride


Asthana, R; Singh, M; Martinez-Fernandez, J
Journal of Alloys and Compounds, 552 (2013) 137-145

ABSTRACT

Copper-base active metal interlayers were used to bond in situ reinforced silicon nitride (Honeywell AS800) at 1317 K for 5 and 30 min in vacuum. The joints were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electron back scattered diffraction (EBSD), and transmission electron microscopy (TEM). A Ti-rich interaction zone (∼3.0–3.5 μm thick) formed at the Si3N4/braze interface. This reaction layer grew toward the inner part of the joint with a featureless microstructure, creating a strong bond. Regions of a Ti-rich phase were frequently found next to the reaction layer but surrounded by the Cu alloy. Extensive Ti and Si enrichments were noted at the interface but there was no evidence of interfacial segregation of Y, La, and Sr (from Y2O3, La2O3 and SrO, added as sintering aids). The reaction layer thickness and composition did not change when brazing time increased from 5 min to 30 min suggesting rapid growth kinetics in the early stages of reaction. The joints were crack-free and showed features associated with plastic deformation, which indicated that the metal interlayer accommodated strain associated with CTE mismatch. The inner part of the joint consisted of highly textured large grains of the braze alloy.


March, 2013 | DOI: 10.1016/j.jallcom.2012.09.104

The distribution of elements in sequentially prepared MgB2 on SiC buffered Si substrate and possible pinning mechanisms


S. Chromik; A. Nishida; V. Strbik; M. Gregor; J.P. Espinós; J. Liday; R. Durny
Applied Surface Science, 269 (2013) 29-32

ABSTRACT

MgB2 thin films are prepared by sequential evaporation of boron and magnesium bilayers on SiC buffered Si substrates followed by an in situ annealing. Precursor Mg–B bilayers are deposited by electron beam evaporation at room temperature. The amount of B is varied so as to result in different thickness (15 nm and 50 nm) of stoichiometric MgB2 final film after an in situ reaction with the excess Mg top layer in the vacuum. We show the distribution of the elements through the film.

X-ray photoelectron spectroscopy analyses have shown that carbon is not free in the films (except the surface of the film) and silicon is in the compound form, too. In the case of the 15 nm thick films we see a strong interdiffusion of the elements (C, B) and we observe a suppression of TC of the film to 20 K. We register different slope of the HC2(T)HC2(T) dependence – the lowest temperature value of HC2HC2 for the 15 nm thick film exceeds the one for the 50 nm thick film in spite of lower TC. We suppose that δl pinning mechanism is dominant for the 15 nm thick film.


March, 2013 | DOI: 10.1016/j.apsusc.2012.10.019

Growth of silver on ZnO and SnO2 thin films intended for low emissivity applications


Alvarez, R; Gonzalez, JC; Espinos, JP; Gonzalez-Elipe, AR; Cueva, A; Villuendas, F
Applied Surface Science, 268 (2013) 507-515

ABSTRACT

In the present work we have investigated the relationships existing between the optical properties and the growth mechanism, microstructure and surface roughness of SnO2 and ZnO oxide films prepared by magnetron sputtering under conditions resembling those utilized in industry. Thin films of these oxides with different thicknesses were characterized by atomic force microscopy, glancing incidence X-ray diffraction (GIXRD), X-ray reflectometry and spectroscopic ellipsometry. The roughness evolution of the film properties (density, surface roughness and refraction index) as a function of their thickness has been evaluated within the concepts of the Dynamic Scaling Theory of thin film growth. Zinc oxide films were rougher than tin oxide films of similar thickness, indicating a different growing mechanism for the two materials. Silver was evaporated onto the surface of the two oxide thin films and its earlier stages of nucleation studied by background analysis of the X-ray photoemission spectra. A different nucleation mechanism was found depending on the nature of the oxide acting as substrate. The superior performance of the zinc oxide based low emissive coatings is related with a better wetting of silver on the surface of this oxide despite the comparatively lower roughness of the tin oxide layers.


March, 2013 | DOI: 10.1016/j.apsusc.2012.12.156

Cystine-capped CdSe@ZnS nanocomposites: mechanochemical synthesis, properties, and the role of capping agent


Balaz, M; Balaz, P; Tjuliev, G; Zubrik, A; Sayagues, MJ; Zorkovska, A; Kostova, N
Journal of Materials Science, 48 (2013) 2424-2432

ABSTRACT

Cystine-capped CdSe@ZnS nanocomposites were synthesized mechanochemically with the aim to prepare a material which could be used in medicine for biosensing applications. Although synthesized CdSe@ZnS nanocomposites were capped with l-cysteine, cystine was formed from l-cysteine during the milling process. It was proven that water plays the key role in this oxidative transformation. The novel material was characterized by the complex of physico-chemical methods (FTIR, XPS, SEM, EDX, surface area measurements) and CHNS analysis. The leakage of Cd2+ and Zn2+ ions into physiological solution was also studied.


March, 2013 | DOI: 10.1007/s10853-012-7029-3

LaPO4:Er microspheres with high NIR luminescent quantum yield


Garcia-Sevillano, J; Cantelar, E; Justo, A; Ocana, M; Cusso, F
Materials Chemistry and Physics, 138 (2013) 666-671

ABSTRACT

Er-doped LaPO4 microspheres have been synthesized by spray pyrolysis and the near infrared (NIR) properties have been characterized. It has been found that, following an adequate post-annealing treatment, the emission properties are remarkably improved. The NIR luminescence intensity is highly enhanced and its decay time increases to a value almost coincident with the reported radiative lifetime, which implies that the quantum yield approaches η ≈ 100%. This improvement in luminescence characteristics is probably related to the suppression of residual OH− radicals, that otherwise act as NIR luminescence quenchers, and to the increase in material's crystallinity.


March, 2013 | DOI: 10.1016/j.matchemphys.2012.12.036

Hydration properties of synthetic high-charge micas saturated with different cations: An experimental approach


Pavon, E; Castro, MA; Naranjo, M; Orta, MM; Pazos, MC; Alba, MD
American Mineralogist, 98 (2013) 394-400

ABSTRACT

An understanding of the interaction mechanisms between exchangeable cations and layered silicates is of interest from both a basic and an applied point of view. Among 2:1 phyllosilicates, a new family of swelling high-charge synthetic micas has been shown to be potentially useful as decontaminant. However, the location of the interlayer cations, their acidity and the water structure in the interlayer space of these silicates are still unknown. The aim of this paper was therefore to study the hydration state of the interlayer cations in the interlayer space of high-charge expandable micas and to evaluate the effect that this hydration has on the swelling and acidity behavior of these new materials. To achieve these objectives, three synthetic micas with different charge density total layer charges (ranging between 2 and 4 per unit cell) and with five interlayer cations (Na+, Li+, K+, Mg2+, and Al3+) were synthesized and their hydration state, interlayer space, and acidity analyzed by DTA/TG, XRD, and 1H MAS NMR spectroscopy. The results showed that the hydration state depends on both the layer charge and the nature of the interlayer cation. A high participation of the inner-sphere complexes in the highly charged confined space has been inferred and proposed to induce Brønsted acidity in the solid.


March, 2013 | DOI: 10.2138/​am.2013.4217

Preferential oxidation of CO in excess H2 over CuO/CeO2 catalysts: Characterization and performance as a function of the exposed face present in the CeO2 support


Gamarra, D; Camara, AL; Monte, M; Rasmussen, SB; Chinchilla, LE; Hungria, AB; Munuera, G; Gyorffy, N; Schay, Z; Corberan, VC; Conesa, JC; Martinez-Arias, A
Applied Catalysis B: Environmental, 130-131 (2013) 224-238

ABSTRACT

A series of oxidised copper-cerium nanostructured catalysts prepared by impregnation of copper over ceria supports synthesized by different methods (hydrothermal with varying preparation parameters, microemulsion/precipitation), in order to achieve different specific morphologies (nanocubes, nanorods and nanospheres), have been examined with respect to their catalytic properties for preferential oxidation of CO in excess H2 (CO-PROX). The catalysts have been characterized in detail by XRD, Raman, SBET measurement, HREM, XPS, TPR and EPR, which allows establishing a model of structural characteristics of the catalysts. The characterization results have been correlated with analysis of CO-PROX catalytic properties by means of catalytic activity measurements complemented by operando-DRIFTS. Structural dependence of the CO oxidation reaction on the dispersed copper oxide entities as a function of the exposed face present at the surface of the different ceria supports is revealed. An important overall enhancement of the CO-PROX performance is detected for the sample supported on ceria nanocubes which is proposed to be a consequence of the interaction between copper oxide and (1 0 0) faces of the ceria support.


February, 2013 | DOI: 10.1016/j.apcatb.2012.11.008

Multiple Zeolite Structures from One Ionic Liquid Template


Blanes, JMM; Szyja, BM; Romero-Sarria, F; Centeno, MA; Hensen, EJM; Odriozola, JA; Ivanova, S
Chemistry-A European Journal, 19 (2013) 2122-2130

ABSTRACT

This study reports the use of 1-butyl-3-methyl imidazolium methanesulfonate ionic liquid as a template in the synthesis of zeolites. It is found that the silicon source determines the formation of beta (BEA), mordenite framework inverted (MFI), or analcime (ANA) zeolites. Depending on this source, different preorganized complexes are obtained that drive the formation of the different zeolite structures. In the presence of ethanol, the ionic liquid form preorganized complexes that drive the formation of MFI. In its absence, BEA is obtained. Whereas, the large amount of sodium present when using sodium metasilicate leads to ANA formation. A molecular simulation study of the relative stability of the template-framework system and location of the template provides further insight into the mechanism of synthesis.


February, 2013 | DOI: 10.1002/chem.201202556

A Novel 3D Architecture of GdPO4 Nanophosphors: Multicolored and White Light Emission


Becerro, AI; Rodriguez-Liviano, S; Fernandez-Carrion, AJ; Ocaña, M
Crystal Growth & Design, 55 (2013) 454-460

ABSTRACT

Homogeneous monoclinic GdPO4 particles composed of three intersecting lance-shaped crystals forming a penetration twin have been synthesized following a very restrictive, simple, and fast (10 min) method consisting of the hydrothermal reaction of gadolinium acetylacetonate with H3PO4 in a mixture of ethylene glycol and water at 180 °C. Slightly increasing the amount of water in the solvent mixture leads to hexagonal rodlike GdPO4·0.5H2O nanoparticles, whereas the variation of the Gd source, PO4 source, aging temperature, and polyol type gave rise to heterogeneous particles. The synthesis procedure is also suitable for the preparation of Eu3+-, Tb3+-, and Dy3+-doped GdPO4 particles with the same morphology and crystalline structure as the undoped materials. The effect of the doping level on the luminescent properties of the twinlike nanophosphors was evaluated, finding optimum doping levels of 5, 5, and 1% for the Eu3+-, Tb3+-, and Dy3+-doped materials, respectively. The twinlike GdPO4 nanophosphors were found to be more efficient than the rodlike GdPO4 ones in terms of emission intensity. Finally, a solid-state single-phase white-light-emitting nanophosphor has been fabricated for the first time in this system by triply doping the GdPO4 twined particles with appropriate concentrations of Eu3+, Tb3+, and Dy3+ and exciting through the Gd–Ln energy-transfer band at 273 nm. In addition to this energy transfer band, other energy charge transfer processes among the three dopants (Eu3+, Tb3+, and Dy3+) have been observed in the triply doped material.


February, 2013 | DOI: 10.1021/cg301023k

Microwave-Assisted Synthesis of Biocompatible Europium-Doped Calcium Hydroxyapatite and Fluoroapatite Luminescent Nanospindles Functionalized with Poly(acrylic acid)


Escudero, A; Calvo, ME; Rivera-Fernandez, S; de la Fuente, JM; Ocana, M
Langmuir, 29 (2013)

ABSTRACT

Europium-doped calcium hydroxyapatite and fluoroapatite nanophosphors functionalized with poly(acrylic acid) (PAA) have been synthesized through a one-pot microwave-assisted hydrothermal method from aqueous basic solutions containing calcium nitrate, sodium phosphate monobasic, and PAA, as well as sodium fluoride in the case of the fluoroapatite particles. In both cases a spindlelike morphology was obtained, resulting from an aggregation process of smaller subunits which also gave rise to high specific surface area. The size of the nanospindles was 191 (32) × 40 (5) nm for calcium hydroxyapatite and 152 (24) × 38 (6) nm for calcium fluoroapatite. The luminescent nanoparticles showed the typical red luminescence of Eu3+, which was more efficient for the fluoroapatite particles than for the hydroxyapatite. This is attributed to the presence of OH– quenchers in the latter. The nanophosphors showed negligible toxicity for Vero cells. Both PAA-functionalized nanophosphors showed a very high (up to at least 1 week) colloidal stability in 2-(N-morpholino)ethanesulfonic acid (MES) at pH 6.5, which is a commonly used buffer for physiological pH. All these features make both kinds of apatite-based nanoparticles promising tools for biomedical applications, such as luminescent biolabels and tracking devices in drug delivery systems.


February, 2013 | DOI: 10.1021/la304534f

Laser induced enhancement of dichroism in supported silver nanoparticles deposited by evaporation at glancing angles


Filippin, AN; Borras, A; Rico, VJ; Frutos, F; Gonzalez-Elipe, AR
Nanotechnology, 24 (2013) 045301

ABSTRACT

Silver nanoparticles (NPs) depicting well defined surface plasmon resonance (SPR) absorption were deposited on flat substrates by physical vapor deposition in a glancing angle configuration. The particles were characterized by scanning electron microscopy and atomic force microscopy and their optical properties examined by UV–vis absorption spectroscopy using linearly polarized light. It was found that, depending on the amount of deposited silver and the evaporation angle, part of the 'as-prepared' samples present NPs characterized by an anisotropic shape and a polarization dependent SPR absorption and different colors when using polarized white light at 0° and 90°. Low-power irradiation of these materials with an infrared Nd-YAG nanosecond laser in ambient conditions produced an enhancement in such dichroism. At higher powers, the dichroism was lost and the SPR bands shifted to lower wavelengths as a result of the reshaping of the silver NPs in the form of spheres. The possible factors contributing to the observed changes in dichroism are discussed.


February, 2013 | DOI: 10.1088/0957-4484/24/4/045301

Growth regimes of porous gold thin films deposited by magnetron sputtering at oblique incidence: from compact to columnar microstructures


Alvarez, R; Garcia-Martin, JM; Macias-Montero, M; Gonzalez-Garcia, L; Gonzalez, JC; Rico, V; Perlich, J; Cotrino, J; Gonzalez-Elipe, AR; Palmero, A
Nanotechnology, 24 (2013) 045604

ABSTRACT

Growth regimes of gold thin films deposited by magnetron sputtering at oblique angles and low temperatures are studied from both theoretical and experimental points of view. Thin films were deposited in a broad range of experimental conditions by varying the substrate tilt angle and background pressure, and were analyzed by field emission scanning electron microscopy and grazing-incidence small-angle x-ray scattering techniques. Results indicate that the morphological features of the films strongly depend on the experimental conditions, but can be categorized within four generic microstructures, each of them defined by a different bulk geometrical pattern, pore percolation depth and connectivity. With the help of a growth model, a microstructure phase diagram has been constructed where the main features of the films are depicted as a function of experimentally controllable quantities, finding a good agreement with the experimental results in all the studied cases.


February, 2013 | DOI: 10.1088/0957-4484/24/4/045604

Efficient and affordable hydrogen production by water photo-splitting using TiO2-based photocatalysts


Melian, EP; Diaz, OG; Mendez, AO; Lopez, CR; Suarez, MN; Rodriguez, JMD; Navio, JA; Hevia, DF; Pena, JP
International Journal of Hydrogen Energy, 38 (2013) 2144-2155

ABSTRACT

TiO2-based photocatalyst materials were synthesized through a sol–gel method, followed either by: (1) hydrothermal treatment (150 °C/24 h), or (2) heat treatment (calcination) in a temperature range between 400 and 900 °C. The resulting materials were characterized through BET, XRD, TEM, FTIR, RAMAN, laser diffraction and UV–Vis Diffuse Reflectance Spectroscopy. Photoactivity of the various materials was checked against photocatalytic water-splitting for hydrogen production and a relationship between TiO2 structure and hydrogen production capacity was identified. Optimum results were obtained for anatase-rutile mixtures in a ratio of 87:13. The activity of the home-made photocatalysts was also compared (under the same conditions) with the best commercially available materials which have been widely described in the literature: Hombikat UV100, Millenium PC100, Kronos vlp7000,Degussa P25and Kemira 625.


February, 2013 | DOI: 10.1016/j.ijhydene.2012.12.005

Effects of plasma surface treatments of diamond-like carbon and polymeric substrata on the cellular behavior of human fibroblasts


Lopez-Santos, C; Fernandez-Gutierrez, M; Yubero, F; Vazquez-Lasa, B; Cotrino, J; Gonzalez-Elipe, A; San Roman, J
Journal of Biomaterials Applications, 27 (2013) 669-683

ABSTRACT

Surface properties play an important role in the functioning of a biomaterial in the biological environment. This work describes the influence of the changes that occurred on diamond-like carbon (DLC) and polymeric substrata by different nitrogen and ammonia plasmas treatments and its effects on the cell proliferation on these materials. All substrata were additionally subjected to the effect of neutral beams of nitrogen atoms and NH species for comparison purposes. Results about the proliferation, viability, and morphology of fibroblasts were correlated with surface chemical composition, surface tension, and topography. It was found that the presence of amine groups on the surface and the surface tension are beneficial factors for the cell growth. Surface roughness in DLC also plays a positive role in favoring cell adhesion and proliferation, but it can be detrimental for some of the treated polymers because of the accumulation of low molecular weight fragments formed as a result of the plasma treatments. Analysis of the overall results for each type of material allowed to define a unique parameter called ‘factor of merit’ accounting for the influence of the different surface characteristics on the cell deployment, which can be used to predict qualitatively the efficiency for cell growth.


February, 2013 | DOI: 10.1177/0885328211422832

Comments on “Thermal decomposition of pyridoxine: an evolved gas analysis-ion attachment mass spectrometry study”. About the application of model-fitting methods of kinetic analysis to single non-isothermal curves


Sanchez-Jimenez, PE; Perez-Maqueda, LA; Perejon, A; Criado, JM
Rapid Communications in Mass Spectrometry, 27 (2013) 500-502

ABSTRACT

Improved photocatalytic activity of g-C3N4/TiO2 composites prepared by a simple impregnation method


Miranda, C; Mansilla, H; Yanez, J; Obregon, S; Colon, G
Journal of Photochemistry and Photobiology A: Chemistry, 253 (2013) 16-21

ABSTRACT

g-C3N4 and TiO2 hybrid structures are synthesized by means of a simple impregnation method having good photoactivities for the degradation of phenol under UV irradiation. From the wide structural and surface characterization we have stated that the presence of g-C3N4 notably affect the surface feature of TiO2 (surface area and pore size distribution). Enhanced photoactivities have been obtained for composites systems. The best result was obtained for 2 wt% loading of g-C3N4 leading to a 70% of improvement with respect to bare TiO2 in the reaction rate. The effective charge carrier separation was proposed as the responsible of such improved photoactivity.


February, 2013 | DOI: 10.1016/j.jphotochem.2012.12.014

Kinetic approach to partially overlapped thermal decomposition processes


Koga, N; Goshi, Y; Yamada, S; Perez-Maqueda, LA
Journal of Thermal Analysis and Calorimetry, 111 (2013) 1463-1474

ABSTRACT

Practical usefulness of the kinetic deconvolution for partially overlapped thermal decomposition processes of solids was examined by applying to the co-precipitated basic zinc carbonate and zinc carbonate. Comparing with the experimental deconvolutions by thermoanalytical techniques and mathematical deconvolutions using different statistical fitting functions, performance of the kinetic deconvolution based on an accumulative kinetic equation for the independent processes overlapped partially was evaluated in views of the peak deconvolution and kinetic evaluation. Two-independent kinetic processes of thermal decompositions of basic zinc carbonate and zinc carbonate were successfully deconvoluted by means of the thermoanalytical measurements in flowing CO2 and by applying sample controlled thermal analysis (SCTA). The deconvolutions by the mathematical curve fittings using different fitting functions and subsequent formal kinetic analysis provide acceptable values of the mass-loss fractions and apparent activation energies of the respective reaction processes, but the estimated kinetic model function changes depending on the fitting functions employed for the peak deconvolution. The mass-loss fractions and apparent kinetic parameters of the respective reaction processes can be optimized simultaneously by the kinetic deconvolution based on the kinetic equation through nonlinear least square analysis, where all the parameters indicated acceptable correspondences to those estimated through the experimental and mathematical deconvolutions. As long as the reaction processes overlapped are independent kinetically, the simple and rapid procedure of kinetic deconvolution is useful as a tool for characterizing the partially overlapped kinetic processes of the thermal decomposition of solids.


February, 2013 | DOI: 10.1007/s10973-012-2500-6

Allochthonous red pigments used in burial practices at the Copper Age site of Valencina de la Concepción (Sevilla, Spain): characterisation and social dimension


Rogerio-Candelera, MA; Herrera, LK; Miller, AZ; Sanjuan, LG; Molina, CM; Wheatley, DW; Justo, A; Saiz-Jimenez, C
Journal of Archaeological Science, 40 (2013) 279-290

ABSTRACT

The use of red pigments linked to burial practices is widely documented in the Iberian prehistoric record and very often it has been traditionally interpreted as a ritual practice entailing the utilisation of local raw materials (iron oxides). Some research works, nevertheless, have also detected the use of red pigments which can only be interpreted as allochthonous. The red pigments spread over a single inhumation in a monumental Megalithic tomb surrounding Valencina de la Concepción Copper Age settlement was studied by means of X-ray diffraction, field emission scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray microfluorescence, micro-Raman and Fourier transform infrared spectroscopies. This approach allowed characterising the red pigments as cinnabar, mixed with tiny amounts of iron oxides. The presence of cinnabar, a product that was necessarily imported, in a context of an exceptional set of grave goods, suggests that the use of cinnabar was linked not only to ritual but also to practices related to the display of social status.


February, 2013 | DOI: 10.1016/j.jas.2012.08.004

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