scholarly journals Interpreting the Chemical Variability of Iron Smelting Slag: A Case Study from Northeastern Madagascar

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 900
Author(s):  
Mélissa Morel ◽  
Vincent Serneels
Keyword(s):  
Building Materials ◽  
Archaeological Remains ◽  
X Ray Diffraction ◽  
Mass Balance Calculation ◽  
X Ray ◽  
Iron Smelting ◽  
Chemical Variability ◽  
Smelting Slag ◽  
Main Factors

The archaeological remains of a metallurgical workshop were excavated at Amboronala (northeast of Madagascar/1000–1200 CE). The bulk mineralogical (X-ray Diffraction) and chemical (X-ray Fluorescence) data on ores, building materials, and slag are used to carry out a mass balance calculation. The results show an important variability from one smelt to the other, reflecting a poorly controlled process. During each smelt, a given amount of building material contributes to the formation of the slag, and the conditions of reduction allow the extraction of a given amount of metal. These two main factors influence the composition of the slag independently and variably. This finding allows to make some inference on the origin of the technique and the organization of the production can be made.

scholarly journals Magnesium Oxybromides MOB-318 and MOB-518: Brominated Analogues of Magnesium Oxychlorides

2020 ◽  
Vol 10 (11) ◽  
pp. 4032
Author(s):  
Anna-Marie Lauermannová ◽  
Michal Lojka ◽  
Filip Antončík ◽  
David Sedmidubský ◽  
Milena Pavlíková ◽  
...  
Keyword(s):  
Building Materials ◽  
Simultaneous Thermal Analysis ◽  
Heating Process ◽  
X Ray Diffraction ◽  
Sustainable Building ◽  
X Ray ◽  
Environmentally Sustainable ◽  
Transmission Electron ◽  
Magnesium Oxychloride ◽  
Sustainable Building Materials

The search for environmentally sustainable building materials is currently experiencing significant expansion. It is increasingly important to find new materials or reintroduce those that have been set aside to find a good replacement for Portland cement, which is widely used despite being environmentally insufficient and energy-intensive. Magnesium oxybromides, analogues to well-known magnesium oxychloride cements, fit both categories of new and reintroduced materials. In this contribution, two magnesium oxybromide phases were prepared and thoroughly analyzed. The stoichiometries of the prepared phases were 5Mg(OH)2∙MgBr2∙8H2O and 3Mg(OH)2∙MgBr2∙8H2O. The phase analysis was determined using X-ray diffraction. The morphology was analyzed with scanning and transmission electron microscopy. The chemical composition was studied using X-ray fluorescence and energy dispersive spectroscopy. Fourier transform infrared spectroscopy was also used. The thermal stability and the mechanism of the release of gasses linked to the heating process, such as water and hydrobromic acid evaporation, were analyzed using simultaneous thermal analysis combined with mass spectroscopy. The obtained results were compared with the data available for magnesium oxychlorides.

scholarly journals The Case Study of the Medieval Town Walls of Gubbio in Italy: First Results on the Characterization of Mortars and Binders

Heritage ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 468-478 ◽  
Author(s):  
Fernanda Carvalho ◽  
Andreia Lopes ◽  
Antonella Curulli ◽  
Teresa da Silva ◽  
Maria Lima ◽  
...  
Keyword(s):  
Polarized Light ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heritage Sites ◽  
First Results ◽  
Restoration Practices ◽  
Climate Events

Good conservation and restoration practices of cultural heritage assets rely on the knowledge of original materials. In the framework of the HERACLES Project (HERACLES—HEritage Resilience Against CLimate Events on Site, H2020 Grant Agreement 700395), dealing with the effects of climatic actions and natural hazards on built heritage, a set of important heritage sites are currently under study to improve their resilience against climate events. Among these are the medieval Gubbio Town Walls in Italy. The present work focuses on the mortars and binders of this monument and collected samples related to different parts of the Walls, corresponding to various historical periods of construction and interventions. They were characterized to determine their minerochemical composition, thermal behavior, and morphology. For that purpose, ex-situ laboratory techniques, such as X-ray diffraction (XRD), wavelength dispersive X-ray fluorescence (WDXRF), optical microscopy (OM), polarized light microscopy (PLM), scanning electron microscopy (SEM), and simultaneous differential thermal analysis and thermogravimetry (TG-DTA) were used to discern trends in different sampling areas due to construction/reconstruction periods and building techniques.

scholarly journals X-ray diffraction study on new organic- natural building materials

2018 ◽  
Vol 22 ◽  
pp. 372-379 ◽  
Author(s):  
Raluca Fernea ◽  
Iacob Florea ◽  
Daniela Lucia Manea ◽  
Petru Pășcuță ◽  
Daniela Roxana Tămaș-Gavrea
Keyword(s):  
Diffraction Study ◽  
Building Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Natural Building

scholarly journals HUMAN AMYLOID PROTEIN: CHEMICAL VARIABILITY AND HOMOGENEITY

1971 ◽  
Vol 19 (1) ◽  
pp. 1-15 ◽  
Author(s):  
M. HARADA ◽  
C. ISERSKY ◽  
P. CUATRECASAS ◽  
D. PAGE ◽  
H. A. BLADEN ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amyloid Fibril ◽  
Gel Filtration ◽  
Protein S ◽  
Amyloid Protein ◽  
X Ray Diffraction ◽  
Amyloid Proteins ◽  
X Ray ◽  
Chemical Variability ◽  
Sepharose 4B

The morphology of the fibril of amyloid derived from different individuals is similar, but occasionally significant differences are noted. All human amyloid filaments have a "β-pleated sheet" conformation as revealed by x-ray diffraction, and those examined after orientation show a "cross-β" pattern. All amyloid fibril concentrates studied so far can be fractionated to obtain the major amyloid protein component(s) by sequential gel filtration with 5 M guanidine-HCl in 1 N acetic acid on Sepharose 4B and Sephadex G-100 or G-75 columns with the removal of over 28% of proteins representing minor constituents. The major amyloid protein(s) obtained from the spleen and/or liver of six patients is found to contain tryptophan, to be deficient in hydroxylysine and hydroxyproline and usually at least one commonly occurring amino acid and to have a high content of dicarboxylic acid and short chain amino acids and unreactive (blocked) NH2-terminal groups or aspartic acid-asparagine (Asx). However, the amyloid protein(s) from each individual differs from that of the others in molecular weight, in amino acid composition and in the presence or absence of specific tryptic peptides. Amyloid protein(s) from the liver and spleen of the same individual is identical. No chemical characteristics distinguish amyloid proteins derived from cases classified clinically as "primary" from those classified as "secondary." There is a striking chemical similarity between amyloid proteins and the NH2-terminal variable fragment of the light and heavy chain of immumoglobulin proteins.

scholarly journals X-Ray Diffraction and Theoretical Calculation–Supported Formation of Polymorphic Cocrystals Discovered Through Thermal Methods: A Case Study

2019 ◽  
Vol 108 (10) ◽  
pp. 3340-3347 ◽  
Author(s):  
Zhengzheng Zhou ◽  
Mónica Calatayud ◽  
Julia Contreras-García ◽  
Liang Li ◽  
Henry H.Y. Tong ◽  
...  
Keyword(s):  
Theoretical Calculation ◽  
X Ray Diffraction ◽  
Thermal Methods ◽  
X Ray

scholarly journals High Throughput Screening and Characterization Methods of Jordanian Oil Shale as a Case Study

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3148 ◽  
Author(s):  
Ziad Abu El-Rub ◽  
Joanna Kujawa ◽  
Esra’a Albarahmieh ◽  
Nafisah Al-Rifai ◽  
Fathieh Qaimari ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
Oil Shale ◽  
Analytical Techniques ◽  
Economic Feasibility ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Characterization Methods ◽  
X Ray ◽  
Hydrogen Mass

Oil shale is an important possible solution to the problem of energy in Jordan. To explore the technical and the economic feasibility of oil shale deposits, numerous samples are analyzed using the standard Fischer Assay (FA) method. However, it would be useful to develop faster, cheaper, and reliable methods for determining the oil content of oil shale. Therefore, the aim of this work was to propose and investigate rapid analytical techniques for the screening of oil shale deposits and to correlate them with the FA method. The Omari deposit located east of Jordan was selected as a case study for analysis using thermogravimetric analysis (TGA) coupled with Fourier-transform infrared (FTIR), differential scanning calorimetry (DSC), elemental analysis, X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analysis. Results obtained from the TGA method were linearly correlated with FA with high regression factor (R2 = 0.99); a quadratic correlation (R2 = 0.98) was maintained between the FA and the elemental hydrogen mass content, and a quadratic correlation (R2 = 0.97) was found between the FA and the aliphatic hydrocarbons (FTIR peak at 2927 cm−1) produced in the pyrolysis zone. Although other techniques were less correlated, further investigation might lead to better results. Subsequently, these correlated techniques can be a practical alternative to the conventional FA method when, in particular, specific correlation is made for each deposit.

Centrosymmetric or Noncentrosymmetric? Case Study, Generalization and Structural Redetermination of Sr5Nb5O17

1998 ◽  
Vol 54 (4) ◽  
pp. 399-416 ◽  
Author(s):  
S. C. Abrahams ◽  
H. W. Schmalle ◽  
T. Williams ◽  
A. Reller ◽  
F. Lichtenberg ◽  
...  
Keyword(s):  
Niobium Oxide ◽  
The Novel ◽  
Physical Measurement ◽  
X Ray Diffraction ◽  
Acta Cryst ◽  
Data Set ◽  
Space Group ◽  
X Ray ◽  
Atomic Coordinates

The possibility that the structure of the novel semiconducting perovskite-related material strontium niobium oxide, Sr5Nb5O17, refined by Schmalle et al. [Acta Cryst. (1995), C51, 1243–1246] in space group Pnn2, might instead belong to space group Pnnm has been investigated following an analysis of the atomic coordinates that indicated the latter space group to be more likely. All I obs were carefully remeasured, first those within a hemisphere containing c *, then all that lay within the full sphere of reflection. Refinement was undertaken, with each of two different sets of weights, in each space group. Each data set was used under three limiting intensity conditions: I obs > 4σ(I obs), I obs > 2σ(I obs) and finally with all reflections, but setting magnitudes with I obs ≤ 0 equal to 0. Fourteen separate tests based only upon the X-ray diffraction data may be used to distinguish between Pnn2 and Pnnm. Nine tests favored the latter choice, four were indeterminate and one was not used. Seven further tests may be made on the basis of physical measurement; of these, three strongly indicated Pnnm, one was indeterminate and three could not be used. The evidence clearly suggests the space group is Pnnm. The use of all reflections, including those with negative magnitude set equal to zero, is essential to avoid ambiguity in the X-ray diffraction tests and achieve the highest reliability. Refinement with weights based on variances of Type A and Type B [Schwarzenbach et al. (1995). Acta Cryst. A51, 565–569] resulted in improved reliability compared with that obtained from a popular empirical weighting scheme. The revised structure differs in several respects from that published previously.

scholarly journals Influence of ThO2 on the photocatalytic activity of TiO2

2011 ◽  
Vol 9 (6) ◽  
pp. 1027-1038 ◽  
Author(s):  
Radina Kralchevska ◽  
Maria Milanova ◽  
Petya Kovacheva ◽  
Jovo Kolev ◽  
Georgi Avdeev ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Relative Content ◽  
X Ray Diffraction ◽  
Doping Agent ◽  
X Ray ◽  
Decay Products ◽  
Degradation Rate Constant ◽  
Main Factors ◽  
Sol Gel Synthesis

AbstractMicrocomposites consisting of TiO2 (or Ce-doped TiO2) and ThO2 (0.5–2% of the TiO2 mass) are produced by sol-gel synthesis of TiO2 in presence of ThO2. X-ray diffraction study reveals the effects of ThO2 (compared to the ThO2-free TiO2, obtained by the same method) on the anatase interplanar distances, crystallites size and phase composition. The photocatalytic tests in presence of the composites under UV irradiation reveal an increase of the Malachite Green degradation rate constant. The effect depends on the Th relative content, temperature of annealing of the catalyst and addition of other doping agent. The highest photocatalytic activity is observed for TiO2 obtained at 550°C and containing 1% ThO2. The composite exhibits activity in dark, also. The presence of Ce4+ ions is not an obligatory requirement for the realization of the ThO2 effect. The reported results suggest that the radioactivity of the Th and/or its decay products is one of the main factors responsible for the increased photocatalytic activity of TiO2.

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