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Copyright of Revista Ciencia y Tecnología Agropecuaria is the property of Agrosavia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Al-Si alloys, with concentrations of 10, 30, 50 and 70% Si weight, have been synthesized by mechanical alloy and characterized by DRX, MEB, DSC and Impedance. For alloy powders X-rays detected only diffractions of Al- and Si- relevant to the cubic system, with space group Fm-3m for Al and Fd-3m for Si; The aAl and aSi network parameters showed different behaviors depending on whether the alloy is hypoeutectic or hypereutectic. The crystallite sizes decrease as the grinding time increases independently of the Si concentration to a final value between 25 to 30 nm at 40 hours of grinding; The relative deformation for hyper eutectic Si concentrations increases with the Si concentration and tends to grow at milling times greater than 40 hours. Microscopy reveals changes in morphology with the Si concentration and EDS analyses show the presence of oxygen, iron, and carbon. Density decreases with increasing Si amount and with increasing grinding time. The impedance techniques are shown as a useful tool in the characterization of alloys, reflecting a different behavior for hypoeutectic and hypereutectic structures. The electrical resistivity values reported in this work are framed between the limit values established for two phase isotropic composites. The calorimetric study reflects a single endothermic reaction around 579 °C and 567 °C, for hypo and hyper eutectic alloys, which analyzed by deconvolution and the kinetic method of Sestak-Berggren was mainly associated with the eutectic transformation reported in the phase diagram. The presence of oxygen in the most loaded samples decreases the value of said temperature and its enthalpy. [ABSTRACT FROM AUTHOR]

Copyright of Revista del Museo de Antropología is the property of Museo de Antropologia - IDACOR and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The following study proposes to analyze one of the most characteristic pigments of the Cañete Valley during the Middle Horizon period, specifically, the green-yellowish color in the Cerro de Oro ceramic repertoire. Defining the origin and use of this pigment allows for a better understanding of the access to raw materials and the operational chain in the manufacture of one of the ceramics that define this regional development. Ceramic fragments with the greenish pigment and epidote samples, both found at the Cerro de Oro archaeological site, have been used as samples for this study. To define the chemical and mineralogical composition of the pigment, XRF, Raman and XRD analyses were carried out. These analyses have allowed us to identify epidote as the colored mineral, and its behavior at high temperatures suggests that this mineral could be related to the pigment found in the ceramics of the site. [ABSTRACT FROM AUTHOR]

We synthesized two Mg-In alloys, namely, Mg 50% In (17.47% at. In) and Mg 75% In (38.84% at. In) by subjecting high purity Mg and In powders to mechanical alloying. The synthesis was followed in each case by X-ray diffraction (XRD), which allowed for the identification of a series of Mg-In metastable phases that occurred during the alloying process. The invariability of the diffraction patterns made it possible for the grinding time to be set at 10 hours, phases In0.144 Mg1.856 and In0.212 Mg 1.788 and phases InMg and InMg3 having the greatest presence in the Mg 17.47% at. In and Mg 38.84% at. In alloys, respectively. Samples thermally annealed at 300 and 400 ºC were studied by differential scanning calorimetry (DSC) and electrical resistivity (Δρ). DSC measurements showed a series of endothermal phases according to what is established in the phase diagram of the Mg-In system. A kinetic analysis of the first reactions in both alloys after annealing at 300 ºC evinced that they occurred by indium diffusion in the Mg matrix. When the annealing was at 400 ºC, however, above the solubility limit of both β1 in the case of Mg 17.47% at. In; and β2 in that of Mg 38.84% at In, reactions revealed low activation energy, mainly due in the first case to the migration of In atoms in the Mg solid solution, and to the order-disorder transition effects in the second. This behavior was ratified by Δρ measurements. [ABSTRACT FROM AUTHOR]

We present the results of the chemical and mineralogical composition analysis, by means of XRF, RAMAN and DRX, of the post-fired paint used to decorate Early Paracas ceramic vessels from the Puerto Nuevo site, on the south-central coast of Peru. The characterization of these pigments allows us to approach the mechanisms used by the inhabitants of the Pisco valley from the 9th to the 6th centuries BC to obtain these raw materials. We speculate about the existence of a combination of strategies that include direct access to obtain hematite and antlerite available from nearby sources, and horizontal coast-coast exchange, as well as vertical coast-sierra exchange, using llama caravans, to procure respectively anatase, in the first case, and cinnabar, realgar, orpiment and pararealgar, in the other, from more distant sources. [ABSTRACT FROM AUTHOR]

The objective of this article was to analyze the effect of thermal oxidation on microstructural change and hardness properties of Ti6Al4V alloy. Titanium samples were subjected to a thermal oxidation treatment from 450°C to 850°C for 2 hours with slow cooling. The superficial morphology was analyzed by optical microscopy, scanning electron microscopy, X-ray diffraction and hardness analysis. A TiO2 oxide film was generated with thermal oxidation, film that increased its thickness with the temperature. Additionally, this increment of temperature also increased the hardness of the material in 40% at 850°C compared to the material without treatment. The results also showed that entire rutile structures were observed on the surface of the samples from 800°C. [ABSTRACT FROM AUTHOR]

Two natural materials were characterized: The inactive biomass Aspergillus Niger-O5 and the purified Cuban natural zeolite ZNPmed® (NZ), clinoptilolite-type, from the Tajaseras' deposit in Cuba. Both, treated with chemical reagents: the biomass with HCl and Cetyl trimethyl ammonium bromide (CTAB), while the NZ was treated with ammoniac, and NaCl and NaOH dissolutions. The materials were analyzed before and after the treatment by Near-Infrared Spectroscopy (NIRS), Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) to assess likely structural and morphological changes related to its behavior as sorbent. The SEM analysis of the non-treated biomass revealed the presence of thread like structures, showing evident changes only in the biomass treated with CTAB. In the zeolite, the SEM showed that the tabular form is abundant and no change in the morphology after treatment was detected. In the XRD analysis of the zeolite, a signal corresponding to a new phase P was observed. Both, the biomass and the zeolite, increased its sorption capacity for Pt(IV), Pb(II), Cd(II), and Ni(II) after those treatments, which reveals their potential as good sorbents of such contaminants in water. [ABSTRACT FROM AUTHOR]

Copyright of Revista ION is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents the effect on the structural characteristics and magnetic properties of replacement of cations occupying sites A and B, in the crystal structure of BiFeO3 (BFO) in their structural and magnetic properties. The citrate gel method was used to synthesize powders of the systems Bi1-xLaxFeO3 with (x = 0.10, 0.15, 0.20), BiFe1-yCoyO3 (y = 0.03, 0.06, 0.09) and Bi1-xLaxFe1-yCoyO3 with x = 0.10, 0.15, 0.20 and y = 0.03). The obtained powders were subjected to a leaching process to minimize unwanted phases. It was observed, using structural characterization by X-ray diffraction, and morphological characterization by scanning electron microscopy, that cationic substitution alters the crystal structure and the particle size of BFO. Addition of lanthanum and cobalt generates ferromagnetic behaviour reflected in magnetic hysteresis curves obtained at room temperature. [ABSTRACT FROM AUTHOR]

Copyright of La Revista Latinoamericana de Metalurgia y Materiales, RLMM is the property of Universidad Simon Bolivar, Departmento de Ciencia de los Materiales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study shows the high-temperature corrosion resistance of bismuth titanate (BixTiyOz) amorphous thin films deposited by rf sputtering technique. The corrosion test at high temperature were made with 100 cycles in air atmosphere at 600 °C, each cycle consisting 1 hour of heating and 1 hour of cooling. The results of mass loss and corrosion products were characterized by x-ray diffraction (XRD), Auger electron spectroscopy (AES) and scanning electron microscopy (SEM). The results showed a good corrosion resistance up to 60 thermal cycles where a noticeable degradation of the coating was observed. [ABSTRACT FROM AUTHOR]

Shale gas has become a major non-conventional energetical resource. La Luna Formation which is commonly considered as the main petroleum source rock, have also shown to be a major reservoir for shale gas resources. In order to understand the "real" potential of this unit and define exploration strategies, the correlation between compositional and petrophysical patterns. We have analyzed 11 shale samples from La Luna and Conejo Formation in the Middle Magdalena basin and the Eastern Cordillera in order to established its composition, total organic contents, thermal maturity, as well as its total porosity and adsorption capacity. Obtained results suggest that due to its organic content, the presence of quartz and carbonate that these shales have a good quality as a gas reservoir and may have also a moderately good behavior during fracturing. [ABSTRACT FROM AUTHOR]

Copyright of Momento: Revista de Física is the property of Universidad Nacional de Colombia, Departamento de Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Momento: Revista de Física is the property of Universidad Nacional de Colombia, Departamento de Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report characterization of four porous ceramics, C1, C2, C3 and C4, obtained from four polyurethane foams E1, E2, E3 and E4, used as a matrix, and red slurries as reinforcement. The foams were studied with Scanning Electron Microscopy SEM, pore size was determined using the ASTM E1 12 [1], and the chemical composition of red clays was done by X ray diffraction (XRD) [2]. Barbotine of 1.5 g/cm3 density a particle size sieve intern 325 ASTM (45 mm), and a viscosity of 365.3 cP were used. Manufacturing process was by immersion of the foam in the barbotine for 24 hours, then it was subjected to a drying at room temperature for 48 hours and 12 hours in an oven with forced circulation; subsequently, firing took place in an electric muffle at a maximum temperature of 1000 °C for 4 hours. The percentage of porous ceramics was determined by absorption of water by using the NTC 4321-3 [3]. Mechanical resistance to bending was determined according the standard ISO 10545-4 [4] and the grain size by using the ASTM E1 12 [1]. Our the results show an inverse relationship between the density of the foam and the ceramics. The mechanical strength decreases as the porosity increases, and it increases with the grain size. We did not find a clear relationship between the shape and pore size in the foam and the shape and grain size of the ceramics. The properties of the foam used as matrix significantly influence the properties of ceramics obtained from them. The purpose of this paper is to contribute to a method in the manufacture and characterization of porous ceramics to be used at industrial-level processes. [ABSTRACT FROM AUTHOR]

Copyright of Revista Facultad de Ingeniería - UPTC is the property of Universidad Pedagogica y Tecnologica de Colombia, Facultad de Ingenieria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present work it is make a to review of the simplified methods of the X-ray diffraction peak profile analysis of as a powerful tool for the characterization of the structure of polycrystaline materials and to show an example of use of that methods. The considered methods are those of the traditional and modified Williamson- Hall and Warren-Averbach methods. The use of these methods for obtains stacking fault probability, dislocation contrast factors and crystallite size distribution is shown. The methods are applied to a Cu-5 wt.% Cr processed by means mechanical alloying and to a manganese steel obtained by means conventional melting and cold deformed in compression. [ABSTRACT FROM AUTHOR]

In this paper it is analyzed the system La1,5+xBa1,5+x-yCayCu3Oz, based on the production of samples that are in the range of single phase, pure phase, proposed by West [1]. The structural analysis was carried out starting from X Rays Diffraction (XRD), being able to establish a first indication of the presence of pure phase in the system La1,5+xBa1,5+x-yCayCu3Oz , which was corroborated through the refinement Rietveld. Structural parameters of the samples were obtained by the standard method of reaction of solid state. This first indication was also corroborated with measures of Scanning Electronic Microscopy (SEM), and the elementary composition was verifyed through Energy for Dispersion of X Rays (EDX). Finally, and having into account the carried out analysis, it is shown that most of the samples present superconductor characteristics of high planar anisotropy and that although the total range proposed by West corresponds to superconductor systems, not all the samples present pure phase. [ABSTRACT FROM AUTHOR]

Copyright of Ciencia en Desarrollo is the property of Universidad Pedagogica y Tecnologica de Colombia, Centro de Investigaciones y Extension and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ZnSO4 ⋅ 3Zn(OH)2 ⋅ 4H2O(Zinc Sulfate Hidroxide Hidrate) films were obtained on glass substrates by SILAR method. It was employed a precursor solution of ZnSO4 and MnSO4 and water near boiling point complexed with 1 ml of NH4OH as a second solution. Films were treated on air at 300°C by 1 hour. Both films ZnSO4 ⋅ 3Zn(OH)2 ⋅ 4H2O as ZnO are important protective against zinc corrosion because they are passive films that give a longer duration to material, it is therefore relevant to study their response to temperature changes. For those reasons films were analyzed before and after thermal treatment to study the structural and morphological changes by X ray diffraction (XRD), Scanning electron microscopy (SEM) and Raman Microscopy techniques. It was found before thermal treatment by XRD the presence of ZnSO4 ⋅ 3Zn(OH)2 ⋅ 4H2O triclinic phase and after such treatment the ZnO hexagonal phase was evidenced. The morphology identified by SEM before thermal treatment was sheets formed by platelet like structure of micrometric size which changes after thermal treatment to a combination of those sheets with flowers like structure characteristic of ZnO hexagonal. By /it-Raman the hexagonal ZnO phase before thermal treatment as the triclinic ZnSO4 ⋅ 3Zn(OH)2 ⋅ 4H2O phase after thermal treatment were confirmed. One objective of this study was to obtain this protective corrosion material in a controlled manner by techiniques of low cost and high simplicity as Silar method. Which, even under temperture increases continue being protective corrosion although suffers phase changes because new phases have protective corrosive characteristics too. [ABSTRACT FROM AUTHOR]

Copyright of Visión Electrónica is the property of Fondo de Universidad Distrital Francisco Jose de Caldas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ultramarine blue-type inorganic pigments were synthesized using zeolite A, sodium carbonate, elemental sulphur and silver content between 0 and 5 % w/w at 800°C for 4 h. Solids were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy(FT-IR) and UV-visible reflectance spectroscopy to verify the structure and colour of obtained materials. Results showed that the silver in the mixture does not disturb the sodalite structure but the blue colour is modified in this pigment. This could be due to the formation of silver sulphur which does not allow the formation of polysulphurs responsible of the colour and the exchange of silver ions by sodium cations in the sodalite structure. [ABSTRACT FROM AUTHOR]

Introduction: A problem to be solved by modern society is associated with development of biomaterials for prostheses to ensure the replacement of organs and body functions that have been damaged by accident or problems associated to increased life expectancy of population. Poliapatita® is a composite formed by hydroxyapatite (HAP-200), CaCO3 and polyvinyl acetate (POVIAc®). The aims of this work were the physico-chemical and termoanalytical characterization of the composite and the starting materials by means of different techniques: X-Ray Diffraction (DRX), Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). Material and Methods: The working interval used in FT-IR was 500 − 4000 cm-1 with a resolution of 4 cm-1. DRX analysis were accomplished employing the Kα Cu radiation, an angular range (2ϑ) between 20 and 60° and a scan rate of 0.10° angular 2ϑ/min. The temperature was varied from 20 −250 °C and uses a heating speed of 10 °C / min in the DSC analysis. Results and Discussion: The infrared spectrum of Poliapatita® showed that all the mixed signals correspond to the characteristic bands of the starting materials. Through the DRX characterization and the Hanawalt method analysis two crystalline phases were observed corresponding to HAP-200 and CaCO3. In the DSC analysis, the same three POVIAc® signals were observed but with shifts towards to higher temperature values on composite sample. Conclusion: The physico-chemical characterization allowed verifying that there not were any interaction between POVIAc® and the inorganic components. The DSC analysis showed a stabilization of the polymer on Poliapatita® because of an increasing of 70 °C on POVIAc® degradation temperature. [ABSTRACT FROM AUTHOR]

Copyright of Ciencia e Ingenieria Neogranadina is the property of Ciencia e Ingenieria Neogranadina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The scanning electron microscopy (SEM) is commonly used in the areas of corrosion and materials for corrosion failure analysis and materials characterization. In the specific case of microbiologically induced corrosion (MIC) by the action of sulfate-reducing bacteria (SRB), is used quite regularly to characterize biofilms formed on different metal substrates and to identify the morphology of the microorganisms causing the problem; however, very little has been reported correlating the open circuit potential of the metal, sessile bacterial growth of bacteria, biofilm morphology and attack analyzed by SEM and the corrosion products analyzed by SEM-EDX and XRD. That is why in this research, experimental design was structured to allow for these correlations, using a cell electrochemical hydrogen permeation, inoculated in the load cell with the bacterial strain Desulfovibrio desulfuricans subspecies desulfuricans ATCC 7775, for tracking the oxidation-reduction reactions, while the discharge cell was maintained with 0.1 N NaOH to oxidize hydrogen atoms permeated from the load cell with an applied current of 200 mV, which made possible the monitoring of the cathodic reaction of hydrogen reduction by permeation current. The correlation allowed establishing a mechanism of action of these bacteria on carbon steel in media loaded with ferrous ions. [ABSTRACT FROM AUTHOR]

Introduction: A problem to be solved by modern society is associated with development of biomaterials for prostheses to ensure the replacement of organs and body functions that have been damaged by accident or problems associated to increased life expectancy of population. Poliapatita® is a composite formed by hydroxyapatite (HAP-200), CaCO3 and polyvinyl acetate (POVIAc®). The aims of this work were the physico-chemical and termoanalytical characterization of the composite and the starting materials by means of different techniques: X-Ray Diffraction (DRX), Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). Material and Methods: The working interval used in FT-IR was 500-4000 cm-1 with a resolution of 4 cm-1. DRX analysis were accomplished employing the Kα Cu radiation, an angular range (2θ) between 20 and 60° and a scan rate of 0.10° angular 2θ/min. The temperature was varied from 20 - 250 °C and uses a heating speed of 10 °C / min in the DSC analysis. Results and Discussion: The infrared spectrum of Poliapatita® showed that all the mixed signals correspond to the characteristic bands of the starting materials. Through the DRX characterization and the Hanawalt method analysis two crystalline phases were observed corresponding to HAP-200 and CaCO3. In the DSC analysis, the same three POVIAc® signals were observed but with shifts towards to higher temperature values on composite sample. Conclusion: The physico-chemical characterization allowed verifying that there not were any interaction between POVIAc® and the inorganic components. The DSC analysis showed a stabilization of the polymer on Poliapatita® because of an increasing of 70 ®C on POVIAc degradation temperature. [ABSTRACT FROM AUTHOR]

It was described the Li atoms incorporation in MoO3 thin films. Samples were prepared by evaporation using a CO2 Laser working at continuum wave mode. There were used targets with 1%, 2% and 5% (Li ions/Total cations). Samples were characterized with X ray Diffraction (XRD). XRD spectra showed that samples prepared with substrate temperatures lower than 200 \C were amorphous, for higer temperatures, samples grow whith a mixture of the a and b phases of LiMoO3 and Li2MoO4 with orientation through (100), (111) y (012) planes. [ABSTRACT FROM AUTHOR]

This work presents the use of the technique of current pulsant inverse, pulse direct current and direct current for electrodeposition thin films Cu/Cd in double-layer shape on Zamak substrate. The influence of the different variables was studied involved in each one of the processes: voltage and time of deposition (VHigh and tHigh), voltage and time of breakup (VLow and tLow) and the load cycle (θ=tHigh/tHigh+tLow), obtaining as answer the monitory of the average anodic (ILow) and cathodic (IHigh) in function of the time anodic (tLow) and cathodic (tHigh), respectively. The electrodeposits of Cu/Cd was characterized by means ray x diffraction being observed the structure and composition in each one of the films obtained. It was observed that the control pulsant of the voltage during the deposit to influence in the composition of the electrodeposits. [ABSTRACT FROM AUTHOR]

Two groups of samples with compositions Fe100-xNix, with 22.5≤x≤40, were elaborated by elementary mixing of powders and later sintering at 750° C by 3 hours and 1000° C by 1 hour,. For their characterization it were used X-ray diffraction and Mössbauer spectrometry. From the spectra fit the coexistence of the BCC and FCC phases was observed in whole the range of composition studied. The lattice parameters are lightly different from the observed for the elementary powders, indicating dif- fusion of Fe atoms into the Ni lattice and of Ni atoms into the Fe lattice. This effect is bigger in samples sinterized at high temperatures. The fits of the Mössbauer spectra were realized by means of the use of two hyperfine field distributions, each one related to the structural phases found. The hyperfine field distribution for 750 °C are centred at fields about 33T for the BCC component and at 30T for the FCC component. In the case of samples sinterized at 1000°C the average field of the BCC component continues around 33T but the average field of the FCC component ranges around 27T, explainded as due to the contribution of low magnetic fields arounds 10T, this is a typical behavior of Invar alloys. [ABSTRACT FROM AUTHOR]

Structural and morphologic analysis obtained from ITO thin films (indium tin oxide, In2O3:Sn) prepared by the Sol -- gel method, grown on glass substrates, are presented. The films obtained with different number of layers and concentration of glycerine, used as agglutinative material, were characterized by Scanning electron microscopy (SEM) and X-rays diffraction (XRD). The analyses of microscopy show the homogeneity and the grain size (59 - 192 nm) on the surface before and after annealing, as well as the cracking of the film in certain regions due to the changes of the drying and calcination temperature and the composition of the precursor solutions. By means of XRD the cubic structure with a lattice parameter 10.116 Å and its polycrystalline character was determined. Finally, a comparison is done with the structure In2O3. [ABSTRACT FROM AUTHOR]

Mineral ilmenite presents in black beach sands has been high- energy milling at room temperature in air by 10, 20 and 40 hours in attritor mill, and characterised by X-ray diffraction and Mössbauer Spectroscopy. Three ilmenite phases were founded with both techniques. The formation of new phases: gieckelite; suessite; hisingerite and dolomite and a high degree of amorphization with the milling time were detected by XRD. [ABSTRACT FROM AUTHOR]