Molecular and X-ray Spectroscopies for Noninvasive Characterization of Mayan Green Stones from Bonampak, Chiapas

2019 ◽  
Vol 73 (9) ◽  
pp. 1074-1086
Author(s):  
Valentina Aguilar-Melo ◽  
Alejandro Mitrani ◽  
Edgar Casanova-Gonzalez ◽  
Mayra D. Manrique-Ortega ◽  
Griselda Pérez-Ireta ◽  
...  

A burial and a rich offering were found under Room 2 in the Murals Building, Bonampak, a Mayan archaeological site situated in Chiapas, Mexico. This burial may be related with the creation of the famous mural paintings. A rich set of jewelry made of green stones was among the different objects found. Green stones have great importance in Mesoamerican cultures, those composed of jadeite being the most appreciated. To characterize the green stones, different spectroscopic techniques were used in a complementary way: Raman and infrared spectroscopies (FT-IR) were used for global mineralogical analysis, while X-ray diffraction (XRD) and X-ray fluorescence (XRF) were applied simultaneously in situ on the artifacts that were not successfully identified by these molecular techniques. In addition, XRF was used to contrasts the elemental information from pieces composed of pyroxenes that may be related to the raw sources of jade in Guatemala. The main minerals identified within the beads and earrings were jadeite with omphacite and jadeite with albite; to a minor extent, quartz, and serpentine. In this paper, the main features of the molecular and X-ray techniques are compared in order to determine the advantages and limitations of these spectroscopies for mineral identification. With this combination of techniques, it was possible to undertake a suitable characterization of the analyzed objects. This paper focuses on the XRD–XRF combined analysis for in situ noninvasive characterization.

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1498 ◽  
Author(s):  
Abdul Hafeez ◽  
Zareen Akhter ◽  
John F. Gallagher ◽  
Nawazish Ali Khan ◽  
Asghari Gul ◽  
...  

Bis-aldehyde monomers 4-(4′-formyl-phenoxy)benzaldehyde (3a), 3-methoxy-4-(4′-formyl-phenoxy)benzaldehyde (3b), and 3-ethoxy-4-(4′-formyl-phenoxy)benzaldehyde (3c) were synthesized by etherification of 4-fluorobenzaldehyde (1) with 4-hydroxybenzaldehyde (2a), 3-methoxy-4-hydroxybenzaldehyde (2b), and 3-ethoxy-4-hydroxybenzaldehyde (2c), respectively. Each monomer was polymerized with p-phenylenediamine and 4,4′-diaminodiphenyl ether to yield six poly(azomethine)s. Single crystal X-ray diffraction structures of 3b and 3c were determined. The structural characterization of the monomers and poly(azomethine)s was performed by FT-IR and NMR spectroscopic techniques and elemental analysis. Physicochemical properties of polymers were investigated by powder X-ray diffraction, thermogravimetric analysis (TGA), viscometry, UV–vis, spectroscopy and photoluminescence. These polymers were subjected to electrical conductivity measurements by the four-probe method, and their conductivities were found to be in the range 4.0 × 10−5 to 6.4 × 10−5 Scm−1, which was significantly higher than the values reported so far.


Author(s):  
Khalil Faghihi ◽  
Mostafa Ashouri ◽  
Akram Feyzi

<p>A series of nanocomposites consist of organic polyimide and organo-modified clay content varying from 0 to 5 wt%, were successfully prepared by in situ polymerization. Polyimide used as a matrix of nanocomposite was prepared through the reaction of 1,4-bis [4-aminophenoxy] butane (APB) and 3،3΄،4،4΄-benzophenone tetra carboxylic dianhydride (BTDA) in N,N-dimethylacetamide (DMAc). The resulting nanocomposite films were characterized by FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA).</p>


Scanning ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Andrea Gil-Torrano ◽  
Auxiliadora Gómez-Morón ◽  
José María Martín ◽  
Rocío Ortiz ◽  
Mª del Camino Fuertes Santos ◽  
...  

The archaeological site of Cercadilla (Cordoba, Spain) includes a complete chronological sequence from the 3rd to 12th centuries. The most relevant monument is a Roman palace dated between the end of the 3rd century and the beginning of the 4th century AD. It is believed that it was the headquarters of the Emperor Maximiano Herculeo. A bathtub with mural paintings has been found in the thermal zone of the palace. Regarding the occupation of the archaeological site in the medieval period, it should be pointed out that two houses with mural paintings were found; these belong to the Caliphal era (10th-11th centuries). During the Caliphal era, the archaeological site was mostly occupied by one of the large suburbs surrounding the walled city. Cercadilla was gradually abandoned; this process starts at the beginning of the 11th century. This study is focused on the analysis of pigments and preparatory layers of red and white mural paintings of the Roman period in the bath zone and on the analysis of pigments in mural paintings in two houses of the Caliphal era. In the thermal zone, the walls have a white mural painting with vertical and horizontal red bands, while the walls in the two Caliphal houses present the red mural painting decorated with white stripes. Techniques such as Optical Microscopy (OM), Scanning Electron Microscopy in combination with Energy Dispersive X-ray Microanalysis (SEM-EDX), X-ray Diffraction (XRD), micro X-ray Diffraction (μ-XRD), Wavelength Dispersive X-ray Fluorescence (WD-XRF), and Fourier Transform-Infrared Spectroscopy (FT-IR) have been used to study the mural paintings of this archaeological site. The results allowed to determine the composition of the materials used and to understand the differences between the technologies employed in Roman and Caliphal remains studied.


2013 ◽  
Vol 32 (2) ◽  
pp. 171-178 ◽  
Author(s):  
Akram Feyzi ◽  
Khalil Faghihi ◽  
Abdol Ali Zolanvari

AbstractA series of nanocomposites consist of organic polyimide and organo-modified clay content varying from 0 to 10 mass%, were successfully prepared by in situ polymerization. Polyimide used as a matrix of nanocomposite was prepared through the reaction of 1,2-bis(4-aminophenoxy)ethane (BAE) and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) in N,N-dimethylacetamide (DMAC). The resulting nanocomposite films were characterized by FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA).


2021 ◽  
Vol 26 (2) ◽  
Author(s):  
Dorian Polo-Cerón ◽  
María Mercedes Hincapié-Otero ◽  
Andrey Joaqui-Joaqui

N-acylhydrazones 2-(4-chlorophenyl)-N0 -(2-hydroxybenzylidene)acetohydrazide, N0 -(2-hydroxybenzylidene)-2-(4-methoxyphenyl)acetohydrazide, 2-(4-chlorophenyl)-N0 -(2,4-dihydroxybenzylidene)-acetohydrazide, and N0 -(2,4-dihydroxybenzylidene)-2-(4-methoxyphenyl)acetohydrazide were successfully synthesized by a multistep procedure. The obtained organic molecules were characterized by spectroscopic techniques (FT-IR, 1D and 2D NMR, UV-Vis) and mass spectrometry. The structure of 2-(4-chlorophenyl)-N0 -(2-hydroxybenzylidene)acetohydrazide was also confirmed by X-ray diffraction. Ab initio computational simulations of the ligand spectra were in good agreement with experimental data and validated the hypothesis about the existence of a conformational mixture of each ligand in solution. Finally, the complexation potential of the synthesized ligands to Cu2+ was assessed by continuous variation experiments and FT-IR spectroscopy.


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.


2012 ◽  
Vol 600 ◽  
pp. 174-177 ◽  
Author(s):  
Jian Fei Xia ◽  
Zong Hua Wang ◽  
Yan Zhi Xia ◽  
Fei Fei Zhang ◽  
Fu Qiang Zhu ◽  
...  

Zirconia-graphene composite (ZrO2-G) has been successfully synthesized via decomposition of ZrOCl2•6H2O in a water-isopropanol system with dispersed graphene oxide (GO) utilizing Na2S as a precursor could enable the occurrence of the deposition of Zr4+ and the deoxygenation of GO at the same time. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques were used to characterize the samples. It was found that graphene were fully coated with ZrO2, and the ZrO2 existing in tetragonal phase, which resulted in the formation of two-dimensional composite.


2018 ◽  
Vol 73 (12) ◽  
pp. 999-1003 ◽  
Author(s):  
Mohammad Hakimi ◽  
Homeyra Rezaei ◽  
Keyvan Moeini ◽  
Heidar Raissi ◽  
Vaclav Eigner ◽  
...  

AbstractA new cyclotriphosphazene, 2,2,4,4,6,6-hexakis (o-tolylamono)-1,3,5,2λ5,4λ5,6λ5-triazatriphosphinine (MPAP), was prepared using microwave irradiation and identified by elemental analysis, FT-IR, Raman, 31P NMR spectroscopy, and single-crystal X-ray diffraction. In the crystal, in addition to hydrogen bonds, the network is further stabilized by inter- and intramolecular π–π stacking interactions between aromatic rings.


2010 ◽  
Vol 663-665 ◽  
pp. 542-545 ◽  
Author(s):  
Bing Jie Zhu ◽  
Xin Wei Wang ◽  
Mei Fang Zhu ◽  
Qing Hong Zhang ◽  
Yao Gang Li ◽  
...  

The PANI/ITO conducting nanocomposites have been synthesized by in-situ polymerization. The obtained nanocomposites were characterized by X-ray diffraction pattern, scanning electron microscopy and Fourier transform infrared. Electrical conductivity measurements on the samples pressed into pellets showed that the maximum conductivity attained 2.0 ± 0.05 S/cm for PANI/ITO nanocomposites, at ITO doping concentration of 10 wt%. The results of the present work may provide a simple, rapid and efficient approach for preparing PANI/ITO nanocomposites.


2000 ◽  
Vol 15 (7) ◽  
pp. 1617-1621 ◽  
Author(s):  
Jan Schroers ◽  
Konrad Samwer ◽  
Frigyes Szuecs ◽  
William L. Johnson

The reaction of the bulk glass forming alloy Zr41Ti14Cu12Ni10Be23 (Vit 1) with W, Ta, Mo, AlN, Al2O3, Si, graphite, and amorphous carbon was investigated. Vit 1 samples were melted and subsequently solidified after different processing times on discs of the different materials. Sessile drop examinations of the macroscopic wetting of Vit 1 on the discs as a function of temperature were carried out in situ with a digital optical camera. The reactions at the interfaces between the Vit 1 sample and the different disc materials were investigated with an electron microprobe. The structure and thermal stability of the processed Vit 1 samples were examined by x-ray diffraction and differential scanning calorimetry. The results are discussed in terms of possible applications for composite materials.


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