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Abstract  

The crystallisation properties of a mixture of triacylglycerols (TG), cocoa butter (CB) 75%/miglyol 25%, were investigated on cooling at 0.5 °C/min using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The influence of (i) the dispersion of TG within nanoparticles stabilised by proteins, and of (ii) the presence of polar lipids were characterised. In bulk, crystallisation of TG successively occurred with a α 2L (49.3 Å) structure, then the formation of longitudinal stackings of 44.5 and 34.5 Å of β′ form was interpreted as co-crystallisation of TG from CB and miglyol. The dispersion of TG in nanoparticles of about 400 nm induced a higher supercooling and changed their crystallisation properties. The formation of α 49.2 Å and β′ 45 Å structures corresponded to the segregation of TG from CB in solid phases while TG from miglyol remained liquid. Phospholipids with saturated fatty acid chains affected the thermal properties of TG, which demonstrated their localisation at the surface of the nanoparticles. DSC and XRD revealed to be very sensitive and adapted methods to increase the knowledge about the mechanisms of crystallisation in emulsion.

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IfA is a σ-algebra on setX, thenl 0 (X,A) is a barrelled space of class χ0. IfA is an algebra, there are conditions which imply thatl 0 (X,A) is suprabarelled. Here, wheneverA is an algebra, we give conditions forl 0 (X,A) to be not barrelled which are related with the existence of non-trivial convergent sequences.

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Abstract  

Organic waste solutions containing tritium present two problems: the high toxicity of the solvents and the radioactivity of tritium. In this paper the sorption behavior of the radioactivity of tritium from aqueous and organic waste solutions, containing tritium labeled compounds, was studied in Sephadex, mineral coal and alumina. It was found that the tritium retention depends on the composition of the waste solutions. Mineral coal was the best of the three materials studied to retain the organic compounds labeled with this radionuclide.

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Abstract  

This study presents an evaluation of the decomposition kinetic of low-grade nickeliferous laterite by thermogravimetric analysis. Kinetic parameters were calculated using the Ozawa and the iso-conversional Friedman methods. Simplified kinetics models like those based on the reaction order were also applied for the simulations. Two-dimensional shrinkage models of the reaction interface mechanism were adopted as describing the thermal transformation process from non-isothermal kinetic analysis. The iso-conversional method (model-free kinetics) reveals that the decomposition of low-grade nickeliferous laterite does not follow a single mechanism because the determined activation energies and pre-exponential factor are not constant during the course of the reaction.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
G. Ferro-Flores
,
L. García-Salinas
,
M. Pedraza-López
,
M. González-Zavala
,
J. Tendilla
, and
M. López-Gómez

Abstract  

A new type of preparation employing153Sm metallic-hydroxide macroaggregates (153Sm-MHM) for radiation synovectomy was developed. The radiopharmaceutical was prepared by reacting the aqueous solution of153SmCl3 with sodium borohydride solution in 0.5N NaOH. Microscopic analysis showed that153Sm-MHM mean particle size was 4 m (range 1–15 m) avoiding the formation of fine particles (<1 m) which were153Sm-hydroxide macroaggregates preparations (153Sm-HM). Also, suspension properties as sedimentation rate, were better for153Sm-MHM than for153Sm-hydroxyapatite and153Sm-HM. Biological studies in normal rabbits demonstrated high retention into de Knee joint space even at 48 h after administration of153Sm-MHM (>99%).

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Abstract  

New densities are reported over the whole composition range for 1-iodoperfluorohexane+n-octane system at temperatures from 288.15 to 308.15 K at atmospheric pressure. These data have been used to compute the excess molar volumes, V m E. Large positive V m E values have been obtained over the entire range of composition, which increases when the temperature rises. The experimental data were used to calculate the isobaric thermal expansivity, and the quantities (∂V m E/∂T)p and (∂H m E/∂p)T. Furthermore, the results have been used to investigate the volumetric prediction ability of the equations of state Soave–Redlich–Kwong, Peng–Robinson, Patel–Teja and Soave–Redlich–Kwong with volume translation.

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Abstract  

The potential uses of zeolites in the treatment of radioactive wastes may be conditioned to the physico-chemical properties of these materials. This work compares the Co sorption behavior of zeolite 4A and radiation treated zeolite 4A. Sorption experiments were performed with solutions containing labeled cobalt. No radiation effect (100 Mrad) in the zeolite structure or in the Co sorption behavior was found.

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Acta Mathematica Hungarica
Authors:
M. Asensio
,
J. López Ramos
, and
B. Torrecillas
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Journal of Radioanalytical and Nuclear Chemistry
Authors:
H. López-González
,
M. Jiménez-Reyes
,
M. Solache-Ríos
, and
A. Rojas-Hernández

Abstract  

Solubility product (Lu(OH)3(s)⇆Lu3++3OH) and first hydrolysis (Lu3++H2O⇆Lu(OH)2++H+) constants were determined for an initial lutetium concentration range from 3.72·10−5 mol·dm−3 to 2.09·10−3 mol·dm−3. Measurements were made in 2 mol·dm−3 NaClO4 ionic strength, under CO2-free conditions and temperature was controlled at 303 K. Solubility diagrams (pLuaq vs. pC H) were determined by means of a radiochemical method using 177Lu. The pC H for the beginning of precipitation and solubility product constant were determined from these diagrams and both the first hydrolysis and solubility product constants were calculated by fitting the diagrams to the solubility equation. The pC H values of precipitation increases inversely to [Lu3+]initial and the values for the first hydrolysis and solubility product constants were log10 β* Lu,H = −7.92±0.07 and log10 K*sp,Lu(OH)3 = −23.37±0.14. Individual solubility values for pC H range between the beginning of precipitation and 8.5 were S Lu3+ = 3.5·10−7 mol·dm−3, S Lu(OH)2+ = 6.2·10−7 mol·dm−3, and then total solubility was 9.7·10−7 mol·dm−3.

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