Comparative Spectroscopic Analysis of Maya Wall Paintings from Ek’Balam, Mexico

2014 ◽  
Vol 1618 ◽  
pp. 63-72 ◽  
Author(s):  
A. Alonso ◽  
N. A. Pérez ◽  
J. L. Ruvalcaba Sil ◽  
E. Casanova ◽  
P. Claes ◽  
...  

ABSTRACTThe Maya archaeological site of Ek’Balam is located in Yucatán, Mexico. This place is known for its artistic tradition of reliefs modeled in stucco as well as the rich pictorial and hieroglyphic texts. Although the mural played a key role in the artistic program architectural of elite groups, most of these remains have not been studied, either by its incomplete or fragile condition, or by localization in inaccessible substructures.In this study, technical aspects of the mural paintings from rooms 12 and 50 of the main building of the site are addressed by the spectroscopic analysis of its materials. Optical microscopy was used to observe the layers superposition and pigment distribution, while the stucco and rock support were characterized by X-ray Diffraction (XRD) and X-ray Fluorescence (XRF). Moreover, the chromatic palette composed of different colors and tones of red, yellow, orange, green, blue and black were analyzed mainly with non-invasive techniques using Raman and FTIR spectroscopies as well as XRF.The information obtained from the combination of these analytical techniques, allowed a better understanding of the similarities and differences between these two rooms that were built during the last construction stage of the Acropolis. These results were also compared with previous analyses of mural painting of this site and other Maya paintings.

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2365
Author(s):  
Sergio Martínez Moya ◽  
Nuria Boluda Botella

Carbonate scale is one of the main problems in hot water systems, and therefore, interest in this subject has grown since 2000s. Water treatments, based on magnetic and electromagnetic (EM) techniques to prevent scale, are being commercialized, but their effectiveness is not clearly demonstrated because it depends on temperature, pressure, dissolved CO2, pH, field intensity, water flow, etc. In this paper, a review of these techniques, together with other classical techniques, such as chemical softening, the use of inhibitors, ion exchange, electrochemical and membrane treatments is presented. The latter alter the composition of the water and generate hazardous waste for health and the environment, unlike magnetic and EM treatments, which are considered non-invasive techniques. Different hypotheses are used to explain the effect of these treatments, such as the formation of aragonite instead of calcite or crystal nuclei formation within the fluid. Analysis of salts formed with SEM, X-ray diffraction, or colorimetric tests seem to support the efficiency of these treatments since study in the fluid is not easy. Dissolution of the formed scale or its prevention endorse the commercialization of these techniques, but their effectiveness must be verified in each installation.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaojian Bai ◽  
Chen Jia ◽  
Zhigen Chen ◽  
Yuxuan Gong ◽  
Huwei Cheng ◽  
...  

AbstractWith exquisite design and unique style, the painted sculptures of Tutang Buddha and two attendants Buddha in Jingyin Temple are precious cultural heritages of China. The sculpture of Tutang Buddha, which was carved from a mound and painted by ancient craftsmen, was rarely found in ancient China. However, due to natural and human factors, the sculptures were severely damaged. Obviously, they require urgent and appropriate protection and restoration. In this study, samples taken from the sculptures were analysed through multiple analytical techniques, including scanning electron microscopy with energy dispersive spectrometry (SEM–EDS), Raman spectroscopy, X-ray diffraction (XRD), optical microscopy (OM) and granulometry. The analysis results enable us to infer the techniques used by the craftsmen in making the sculptures and provide a reliable evidence for the conservation and future protection of these and similar sculptures.


2012 ◽  
Vol 48 (2) ◽  
pp. 281-290 ◽  
Author(s):  
Noely Camila Tavares Cavalcanti ◽  
Giovana Damasceno Sousa ◽  
Maria Alice Maciel Tabosa ◽  
José Lamartine Soares Sobrinho ◽  
Leila Bastos Leal ◽  
...  

The aim of this study was to characterize three batches of albendazole by pharmacopeial and complementary analytical techniques in order to establish more detailed specifications for the development of pharmaceutical forms. The ABZ01, ABZ02, and ABZ03 batches had melting points of 208 ºC, 208 ºC, and 209 ºC, respectively. X-ray diffraction revealed that all three batches showed crystalline behavior and the absence of polymorphism. Scanning electron microscopy showed that all the samples were crystals of different sizes with a strong tendency to aggregate. The samples were insoluble in water (5.07, 4.27, and 4.52 mg mL-1, respectively) and very slightly soluble in 0.1 M HCl (55.10, 56.90, and 61.70 mg mL-1, respectively) and additionally showed purities within the range specified by the Brazilian Pharmacopoeia 5th edition (F. Bras. V; 98% to 102%). The pharmacopeial assay method was not reproducible and some changes were necessary. The method was validated and showed to be selective, specific, linear, robust, precise, and accurate. From this characterization, we concluded that pharmacopeial techniques alone are not able to detect subtle differences in active pharmaceutical ingredients; therefore, the use of other complementary techniques is required to ensure strict quality control in the pharmaceutical industry.


Author(s):  
Alaa Mohamed Elsafi ◽  
Vinotha Krishnasamy ◽  
Karthik Kannan ◽  
John-John Cabibihan ◽  
Abdulaziz Khalid AlAli ◽  
...  

High levels of glucose or acetone in breath confirms diabetes disease. One of the analytical devices that detect changes in breath is the electrochemical sensor having high selectivity, easy to use and being able to meet diabetic patient’s needs. In this study, sensors were made by fabricating metal oxide coated glassy carbon electrodes and using nafion as a proton conductor. Characterization methods such as X-ray diffraction, FTIR and morphological analysis have been performed for metal oxides to characterize their atomic arrangement and composition. In addition, electrochemical studies were done using Gamry instrument and curves plotted as current in amperes versus voltage to test the coated electrodes conductivity. High selectivity sensors provide promising applications in any field.


2021 ◽  
Vol 6 (4) ◽  
pp. 51
Author(s):  
Luisa Vigorelli ◽  
Elisabetta Croce ◽  
Debora Angelici ◽  
Raffaella Navone ◽  
Sabrina Grassini ◽  
...  

Digital radiography and computed tomography are two fundamental diagnostic techniques in different fields of research, including cultural heritage studies and gemmology. The application of these physical methods of investigation has gained considerable importance as they are non-invasive techniques. The presented work has been mainly focused on micro-tomographic analysis. The project is concerned with the study of natural and cultivated pearls in order to develop an investigation methodology for the analysis, distinction and characterization of different types of pearls, some of them belonging to different precious jewels from private collections. The investigations, carried out on a total of 22 heterogeneous types of pearls, allowed us to establish their origin (natural or cultivated) or to confirm/deny if a hypothesis was already expressed, and as well to highlight the cultivation methodology used case by case. Furthermore, it was possible to ascertain how large and varied the market for cultured pearls is nowadays and how difficult is, in some particular cases, to ascertain their attribution to a certain origin.


2021 ◽  
Vol 234 ◽  
pp. 00106
Author(s):  
Houda Labjar ◽  
Hassan Chaair

The synthesis of apatite silicated Ca10(PO4)6-x(SiO4)x(OH)2-x (SiHA) with 0≤x≤2 was investigated using a wet precipitation method followed by heat treatment using calcium carbonate CaCO3 and phosphoric acid H3PO4 and silicon tetraacetate SiC8H20O4 (TEOS) in medium of water ethanol, with three different silicate concentrations. After drying, the samples are ground and then characterized by different analytical techniques like X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning electron Microscopy (SEM) and chemical analysis.


Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5188
Author(s):  
Iris Raffeis ◽  
Frank Adjei-Kyeremeh ◽  
Uwe Vroomen ◽  
Silvia Richter ◽  
Andreas Bührig-Polaczek

Al-Cu-Li alloys are famous for their high strength, ductility and weight-saving properties, and have for many years been the aerospace alloy of choice. Depending on the alloy composition, this multi-phase system may give rise to several phases, including the major strengthening T1 (Al2CuLi) phase. Microstructure investigations have extensively been reported for conventionally processed alloys with little focus on their Additive Manufacturing (AM) characterised microstructures. In this work, the Laser Powder Bed Fusion (LPBF) built microstructures of an AA2099 Al-Cu-Li alloy are characterised in the as-built (no preheating) and preheat-treated (320 °C, 500 °C) conditions using various analytical techniques, including Synchrotron High-Energy X-ray Diffraction (S-HEXRD). The observed dislocations in the AM as-built condition with no detected T1 precipitates confirm the conventional view of the difficulty of T1 to nucleate on dislocations without appropriate heat treatments. Two main phases, T1 (Al2CuLi) and TB (Al7.5Cu4Li), were detected using S-HEXRD at both preheat-treated temperatures. Higher volume fraction of T1 measured in the 500 °C (75.2 HV0.1) sample resulted in a higher microhardness compared to the 320 °C (58.7 HV0.1) sample. Higher TB volume fraction measured in the 320 °C sample had a minimal strength effect.


2020 ◽  
Vol 10 (9) ◽  
pp. 3035
Author(s):  
Edward Henry Jiménez Calderón ◽  
Ana Emperatriz Paucar Tipantuña ◽  
Paulina Fernanda Herrera Mullo ◽  
Daniel Alejandro Hidalgo Cháfuel ◽  
Washington Ruiz ◽  
...  

The optimal conditions of the catalytic activation of allophane were evaluated for possible use as a catalyst within a fluidized bed catalytic cracking unit (FCC). The physicochemical properties of natural allophane and activated allophane were studied by using an alkaline activating agent, followed by a hydrothermal treatment. For the characterization, analytical techniques were used: Fourier transform infrared spectroscopy, particle size, (BET) surface area, thermogravimetry (TGA), X-ray diffraction (XRD), chemisorption, X-ray fluorescence (XRF), atomic force microscopy (AFM), and chromatography. The catalytic evaluation was determined by the (MAT) micro activity test equipment constructed according to ASTM D-3907/D3907M-2019. In addition, the Navier–Stokes 3D equations (nonlinear partial derivatives) were studied, which allow studying molecular dynamics contributing substantively to chemical kinetics describing the process of decomposition of crude oil in thermal cracking, determining the maximum temperature at which it retains its properties through the action of heat.


2001 ◽  
Vol 73 (4) ◽  
pp. 525-532 ◽  
Author(s):  
MELLATIE R. FINISIE ◽  
ATCHE JOSUÉ ◽  
VALFREDO T. FÁVERE ◽  
MAURO C. M. LARANJEIRA

Bioceramic composites were obtained from chitosan and hydroxyapatite pastes synthesized at physiological temperature according to two different syntheses approaches. Usual analytical techniques (X-ray diffraction analysis, Fourier transformed infrared spectroscopy, Thermo gravimetric analysis, Scanning electron microscopy, X-ray dispersive energy analysis and Porosimetry) were employed to characterize the resulting material. The aim of this investigation was to study the bioceramic properties of the pastes with non-decaying behavior from chitosan-hydroxyapatite composites. Chitosan, which also forms a water-insoluble gel in the presence of calcium ions, and has been reported to have pharmacologically beneficial effects on osteoconductivity, was added to the solid phase of the hydroxyapatite powder. The properties exhibited by the chitosan-hydroxyapatite composites were characteristic of bioceramics applied as bone substitutes. Hydroxyapatite contents ranging from 85 to 98% (w/w) resulted in suitable bioceramic composites for bone regeneration, since they showed a non-decaying behavior, good mechanical properties and suitable pore sizes.


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