Comparative Study of Two Blue Pigments from the Maya Region of Yucatan

2012 ◽  
Vol 1374 ◽  
pp. 115-123
Author(s):  
Silvia Fernández-Sabido ◽  
Yoly Palomo-Carrillo ◽  
Rafael Burgos-Villanueva ◽  
Romeo de Coss
Keyword(s):  
Comparative Study ◽  
Chemical Properties ◽  
Eighth Century ◽  
Blue Pigment ◽  
Spectroscopic Techniques ◽  
Two Samples ◽  
Traditional Preparation ◽  
Maya Blue ◽  
Maya People ◽  
Physical And Chemical

ABSTRACTA comparative study of two blue pigment found in separate megalithic structures in Yucatán México is presented. The first sample (M1) is a piece of turquoise stucco discovered at the top of a building known as Structure-2 in the town of Dzilam González. The second sample (M2) is a residual blue powder that was contained in a Oxcum Café type ceramic vessel recovered in the rubble of the Kabul building in Izamal city. The interest in characterizing these samples increases with the possibility of finding in them evidence of Maya Blue, a dye created in the eighth century by the Maya people, whose extraordinary physical and chemical properties have been studied in laboratories around the world. Maya Blue was a tailored technology used for several centuries, even during the Spanish occupation, throughout Mesoamerica. Despite 80 years of study, the mysteries of its composition, traditional preparation and obsolescence have not yet been fully resolved. Using different spectroscopic techniques (SEM, EDX, XRD, FTIR, UV-Vis DR) we have studied and compared the blue colorants in M1 and M2. Results indicate that M1 is Maya Blue. Despite some similarities in the infrarred vibrational spectra of the two samples, we have determinated that M2 is not Maya Blue but a non-Mesoamerican mineral pigment known as Ultramarine which was probably introduced to America by Europeans.

scholarly journals Impact of Bush Burning on Chemical Properties of Some Soil in Igboora, Oyo State, Nigeria

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
M. A. Adejumobi
Keyword(s):  
Crop Production ◽  
Chemical Properties ◽  
Soil Chemical Properties ◽  
Rooting Depth ◽  
Physical And Chemical Properties ◽  
Land Clearing ◽  
Two Samples ◽  
Burnt Soil ◽  
Physical And Chemical ◽  
And Chemical Properties

Soil is used in agriculture as an anchor and primary nutrient base for plants, and the types of soil and available moisture determine the species of plants that can be cultivated. Bush burning, whether as result of a wildfire or a controlled burning, affects not only the appearance of the landscape, but the quality of the soil. Bush burning method of land clearing is a traditional farming system used as a means of land clearing for crop production. This method of land clearing has both beneficial and detrimental effects on soil physical and chemical properties. Therefore, this study investigated the effects of bush burning on soil chemical properties at different soil depth of 0-30 cm and 30-60 cm respectively base on the rooting depth of crop planted. The experiment was carried out in six selected farms in Igboora, Ibarapa central Local Governmental, Oyo State. The soil sampled were collected from burnt and unburnt experimental soil and analyzed using USDA standard methods for soil analysis for the selected chemical characteristics (pH, Ca2+, Mg2+ Na+. TN and P). Two samples were taken from each burnt and un-burnt locations at depth of 0-30 and 30-60 cm. Paired t-test was used to compare means value of soil chemical properties determined from burnt and un-burnt soil. ANOVA was used for significance difference between soil from burnt and un-burnt soil. pH increased from moderately acidic to slightly acidic, phosphorus content of the soil increased greatly from un-burnt soil to burnt soil at 0-30 cm and 30-60 cm depths from 6.64 to 22.21 ppm and 3.53 to 24.95 ppm, respectively. Similarly, potassium increased from 0.27 to 0.40ppm at 0-30cm depth but decreased from 0.23 to 0.17 ppm at 30-60 cm depth. Nitrogen reduced at both depths from 0.80 to 0.76% and 0.72 to 0.68% respectively. Magnesium also increased from 1.3 cmol/kg to 2.00 cmol/kg and 1.65 to 1.75 cmol/kg at both 0-30 cm and 30-60 cm depth respectively. Whereas calcium showed a reduction from 3.17 to 2.85 cmol/kg and 1.65 to 1.45 cmol/kg at both depths. The variations observed between burnt and un-burnt soil for Ca, Mg, exchangeable acidity, pH, Nitrogen, potassium was significant at p<0.05 probability level. This indicates that bush burning has an impact on soil physical and chemical properties which may affect the suitability of the soil for crop production. Based on this, there is need for environmental education for farmers in the area in order to know the implications of bush burning on soil properties for soil sustainability which will boost food production.

scholarly journals Plasma fluorination of vertically aligned carbon nanotubes: functionalization and thermal stability

2015 ◽  
Vol 6 ◽  
pp. 2263-2271 ◽  
Author(s):  
Claudia Struzzi ◽  
Mattia Scardamaglia ◽  
Axel Hemberg ◽  
Luca Petaccia ◽  
Jean-François Colomer ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Plasma Treatment ◽  
Carbon Nanostructures ◽  
Chemical Properties ◽  
Spectroscopic Techniques ◽  
Multiwalled Carbon ◽  
Desorption Process ◽  
Vertically Aligned ◽  
Physical And Chemical

Grafting of fluorine species on carbon nanostructures has attracted interest due to the effective modification of physical and chemical properties of the starting materials. Various techniques have been employed to achieve a controlled fluorination yield; however, the effect of contaminants is rarely discussed, although they are often present. In the present work, the fluorination of vertically aligned multiwalled carbon nanotubes was performed using plasma treatment in a magnetron sputtering chamber with fluorine diluted in an argon atmosphere with an Ar/F2 ratio of 95:5. The effect of heavily diluted fluorine in the precursor gas mixture is investigated by evaluating the modifications in the nanotube structure and the electronic properties upon plasma treatment. The existence of oxygen-based grafted species is associated with background oxygen species present in the plasma chamber in addition to fluorine. The thermal stability and desorption process of the fluorine species grafted on the carbon nanotubes during the fluorine plasma treatment were evaluated by combining different spectroscopic techniques.

scholarly journals Comparative study of Danshen and Siwu decoction based on the molecular structures of the components and predicted targets

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yang Li ◽  
Li Qiao ◽  
Cong Chen ◽  
Zhenguo Wang ◽  
Xianjun Fu
Keyword(s):  
Comparative Study ◽  
Structural Feature ◽  
3D Structure ◽  
Chemical Properties ◽  
Principal Component ◽  
Molecular Structures ◽  
Physical And Chemical Properties ◽  
Material Basis ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract Background The sentence of “Danshen (Salvia Miltiorrhizae Radix et Rhizoma) and Siwu decoction are similar in function” was first recorded in an ancient Chinese medical book “Fu Ren Ming Li Lun”. This theory has far-reaching influence on the clinical practice of Chinese medicine and is highly respected by Chinese medical doctors. However, the theory has limitations and controversial part for there is no in-depth and system comparative study. Methods We collected the molecular structures of 129 compounds of Danshen and 81 compounds of Siwu decoction from the literatures. MACCS fingerprints and Tanimoto similarity were calculated based on the molecular structures for comparing the structural feature. Molecular descriptors which represent physical and chemical properties were calculated by Discovery Studio. Principal component analysis (PCA) of was performed based on the descriptors. The ADMET properties were predicted by FAF-Drugs4. The effect targets for the compounds with good ADMET properties were confirmed from experimental data and predicted using the algorithm comprising Bernoulli Naive Bayes profiling. Results Based on the molecular structures, the presented study compared the structural feature, physical and chemical properties, ADMET properties, and effect targets of compounds of Danshen and Siwu decoction. It is found that Danshen and Siwu decoction do not have the same main active components. Moreover, the 2D structure of compounds from Danshen and Siwu decoction is not similar. Some of the compounds of Danshen and Siwu decoction are similar in 3D structure. The compounds with good ADMET properties of Danshen and Siwu decoction have same predicted targets, but some have different targets. Conclusions It can be inferred from the result that Danshen and Siwu decoction have some similarities, but also present differences from each other in the structure of the compounds and predicted targets. This may be the material basis of the similar and different traditional efficacy of Danshen and Siwu decoction. The setence of “ Danshen and Siwu decoction are similar in function. “ which is used in clinical has its material basis and target connotation to some extent. However, the traditional effects of Danshen and Siwu decoction are not exactly the same.

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