Otolith-Based Chronology of Brazilian Shellmounds

Radiocarbon ◽  
2019 ◽  
Vol 61 (2) ◽  
pp. 415-433 ◽  
Author(s):  
Carla Carvalho ◽  
Fabiana Oliveira ◽  
Kita Macario ◽  
Tania Lima ◽  
Ingrid Chanca ◽  
...  
Keyword(s):  
Rio De Janeiro ◽  
Brazilian Coast ◽  
X Ray Diffraction ◽  
Geochemical Composition ◽  
X Ray ◽  
Human Bones ◽  
Native Populations ◽  
Micropogonias Furnieri ◽  
Over Time ◽  
Fish Otoliths

ABSTRACTThe radiocarbon (14C) chronology of hunter-fisher-gatherers’ archaeological settlements along the Brazilian coast is usually based on mollusk shells, charcoal from hearths, and eventually human bones. However, fish otoliths are found in several archaeological contexts and may represent a reliable option as a chronological record. In this work, we compare the 14C dates of whitemouth croakers (Micropogonias furnieri) otoliths with dates obtained from other materials (shell and charcoal), collected from shellmounds on the coast of Rio de Janeiro, with the aim of improving the accuracy in the 14C dating of Brazilian shellmounds, strengthening the comprehension of the native populations’ occupational trends and the coeval palaeoceanographic context. Based on x-ray diffraction results for archaeological otoliths, their geochemical composition indicates minimal diagenesis effect over time even under burial conditions in the studied sites. The comparison between otolith dates and dates obtained from other proxies revealed similar results but with decreased deviations in otolith dates in all of the studied sites.

scholarly journals Effect of H2O Activity on Zeolite Formation

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4780
Author(s):  
Claudia Belviso ◽  
Francesco Cavalcante
Keyword(s):  
Liquid Nitrogen ◽  
Sodium Aluminate ◽  
Drying Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lta Zeolite ◽  
Zeolite Formation ◽  
Silica Alumina ◽  
Over Time ◽  
Scanning Electron

In an effort to understand the effects of H2O activity on zeolite formation, we have synthesized LTA zeolite using a combination of freezing processes and varying drying temperatures. Sodium aluminate and sodium silicate were used to form LTA zeolite, according to the IZA (International Zeolite Association) protocol. The synthesis steps were modified by adding the precursor frozen process by a rapid liquid nitrogen (−196 °C) treatment or slow conventional freezer treatment (−20 °C). The samples were subsequently sonicated and then dried at 80 °C or 40 °C. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed on the samples immediately after the drying process as well as after 2 weeks and 1 month of aging the solid products. The results indicated that LTA zeolite does not form. The silica-alumina precursor after both freezing processes and after being dried at 80 °C showed the presence of sodalite displaying stable behavior over time. Both sets of samples dried at 40 °C and did not show the presence of zeolite immediately after the drying process. However, after 2 weeks, the liquid nitrogen–frozen precursor was characterized by the presence of EMT whereas zeolites never formed in the −20 °C samples. These results suggest that freezing processes differently control the H2O activity during the drying and aging processes in the solid state. Thus, although the precursor chemical composition is the same, the type of zeolite formed is different.

scholarly journals Understanding the Crystallinity Indices Behavior of Burned Bones and Teeth by ATR-IR and XRD in the Presence of Bioapatite Mixed with Other Phosphate and Carbonate Phases

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Giampaolo Piga ◽  
David Gonçalves ◽  
T. J. U. Thompson ◽  
Antonio Brunetti ◽  
Assumpció Malgosa ◽  
...  
Keyword(s):  
Crystallinity Index ◽  
Mechanical Processing ◽  
Spectroscopy Data ◽  
X Ray Diffraction ◽  
Human Teeth ◽  
X Ray ◽  
Human Bones ◽  
Burned Bones ◽  
Tcp Phase ◽  
Xrd Patterns

We have critically investigated the ATR-IR spectroscopy data behavior of burned human teeth as opposed to the generally observed behavior in human bones that were subjected to heat treatment, whether deliberate or accidental. It is shown that the deterioration of the crystallinity index (CI) behavior sometimes observed in bones subjected to high temperature appears to be of higher frequency in the case of bioapatite from teeth. This occurs because the formation of the β-tricalcium phosphate (β-TCP) phase, otherwise known as whitlockite, clearly ascertained by the X-ray diffraction (XRD) patterns collected on the same powdered specimens investigated by ATR-IR. These results point to the need of combining more than one physicochemical technique even if apparently well suitable, in order to verify whether the assumed conditions assessed by spectroscopy are fully maintained in the specimens after temperature and/or mechanical processing.

Study and Properties of a Steel Microalloyed Hardened Superficially

2015 ◽  
Vol 365 ◽  
pp. 122-127 ◽  
Author(s):  
N. López-Perrusquia ◽  
M.A. Doñu Ruiz ◽  
C. R. Torres San-Miguel ◽  
M. Flores-Báez ◽  
I. Flores-Báez
Keyword(s):  
Growth Process ◽  
Energy Dispersive Spectrometry ◽  
Boride Layer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffusion Controlled ◽  
Boriding Process ◽  
Kinetics Of ◽  
Over Time ◽  
Scanning Electron

In this study, we present a boronizing treatment on a steel microalloy that was performed according to dehydrated paste-pack boriding. The temperatures conducted were at 1173, 1223 and 1273 K; at various exposure times of 1, 3, 6 and 9 h. As a result of the boriding process, diffusion-controlled growth of the FeB/Fe2B layers was obtained at the surface of the micro-alloy steel, and the kinetics of the growth process changed parabolically over time. The results of these examination properties of the boride layer as revealed by Optical Microscopy (OP) showed the morphology of the boride layer as a saw-tooth with a thickness ranging from 33 μm to 220 μm depending on the boronizing time. The analysis of Scanning Electron Microscopy (SEM-EDS); showed a distribution of the alloying elements that were detected by Energy Dispersive Spectrometry. The X-ray diffraction (XRD) technique indicated that the surface was a mixture of FeB and Fe2B borides. The evaluation of adhesion of the layers was determined by the technique of Rockwell-C hardness. Young’s modulus and hardness of the layer were evaluated by a nanoindentation technique with a load of 250 mN. The paste dehydrate boriding of micro-alloy reveal a change of properties on the surface; also the coatings FeB and Fe2B, to make a sacrificial function in the steels micro alloyed as widely used in pipelines transporting oil.

scholarly journals Estudo de um perfil podzólico e de brunizem da zona oeste do estado do Rio de Janeiro

1990 ◽  
Vol 13 ◽  
pp. 17-29
Author(s):  
Helena Polivanov ◽  
Antonio Carlos Jacome de Castro ◽  
Franklin Dos Santos Antunes ◽  
Luiz Cláudio de Araújo Camara
Keyword(s):  
Grain Size ◽  
Rio De Janeiro ◽  
Atterberg Limits ◽  
Soil Profiles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Physical Measurements ◽  
The City ◽  
Pedogenetic Processes

This work describes the study of two types of soil profiles , podzolic and brunizem . The profiles are localized at Avenida Brasil near the Cabritos viaduct in the city of Rio de Janeiro . Chemical analyses, pH values, sulfuric digestion (SiO2, Al2O3,Fe2O3, TiO2, K2O, Na2O), X-ray diffraction of the clay and silt fractions, mineralogical analyses of sand under the microscope , physical measurements of the Atterberg limits, grain size analyses and specific gravity of solids, were undertaken. The analysed soils have values of the Atterberg limits coherent with the grain size and mineralogy, and the geochemical behavior of the elements analysed is compatible with the pedogenetic processes of formation of these profiles.

scholarly journals GEOCHEMICAL CHARACTERIZATION OF BANANA, BURITI PALM, JUTE AND COIR FIBRES FOR USE AS BIOGEOTEXTILES FOR EROSION CONTROL

2018 ◽  
Vol 26 (3) ◽  
pp. 202-215 ◽  
Author(s):  
Charles Izuchukwu Egbujuo ◽  
Michael A. Fullen ◽  
Antonio J. T. Guerra ◽  
Alexander Iheanyi Opara
Keyword(s):  
Heavy Metal ◽  
Heavy Metal Contamination ◽  
Erosion Control ◽  
X Ray Diffraction ◽  
Soil System ◽  
Geochemical Composition ◽  
X Ray ◽  
Jute Cloth ◽  
High Concentrations ◽  
Banana Leaf

Geochemical analysis of selected plant fibres used as geotextiles for erosion control was conducted to evaluate their geochemical composition and to determine the elements that could potentially be nutrients for plants or cause heavy metal contamination in soils. Analysis of the samples was performed using X-ray Diffraction and X-ray Fluorescence spectrometry. Results revealed that potassium concentrations varied from 3.63% in jute-mat (India)-50.73% in banana-leaf (São Romão, Brazil), with a mean of 27.17%. Similarly, calcium concentrations varied from 0.09% in banana-leaf (São Romão) –37.0% in banana-leaf/stem (Oleo, Brazil). Iron concentrations varied from 0.15% in banana-leaf/stem samples (Oleo) –4.47% in jute-cloth (India). Since banana-leaf/stem had the highest concentration of macro-nutrients, it is therefore proposed that banana-leaf has the highest potential for adding nutrients to the soil system when biodegraded. In addition, heavy metal analysis of the samples revealed that none of the fibres have high concentrations that may contaminate the soil upon decomposition.

scholarly journals Preparation and Characterization of Hydroxyapatite by the precipitation method and heat treatment

2020 ◽  
Vol 9 (6) ◽  
pp. e172963549
Author(s):  
Fellype Diorgennes Cordeiro Gomes ◽  
Julia Didier Pedrosa de Amorim ◽  
Girlaine Santos da Silva ◽  
Karina Carvalho de Souza ◽  
Aline Ferreira Pinto ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tooth Enamel ◽  
Raw Materials ◽  
Calcium Nitrate ◽  
Structural Evolution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Human Bones

Hydroxyapatite is a synthetic substance in the form of microspheres composed of calcium and phosphate, present in human bones and tooth enamel. The objective of the work was to synthesize hydroxyapatite, from the solution of calcium nitrate and diamonic phosphate by the method of precipitation and heat treatment, obtaining the hydroxyapatite in powder form. To study its structural evolution, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Raman spectroscopy were used. The results show that the hydroxyapatite nanocrystalline can be successfully produced by the precipitation technique from raw materials.

scholarly journals Holocene crustaceans from the Tarioba shell mound, Rio das Ostras, Rio de Janeiro, Brazil

Check List ◽  
2016 ◽  
Vol 12 (2) ◽  
pp. 1865 ◽  
Author(s):  
Felipe Barta Rodrigues ◽  
Michelle Rezende Duarte ◽  
Rosa Cristina Corrêa Luz de Souza ◽  
Abílio Soares-Gomes ◽  
Edson Pereira Silva
Keyword(s):  
Rio De Janeiro ◽  
Archaeological Site ◽  
Evolutionary Change ◽  
Taxonomic Group ◽  
Brazilian Coast ◽  
Mollusk Shells ◽  
Group Information ◽  
Over Time ◽  
C14 Method

Crustacean remains from the Tarioba shell mound (Sambaqui da Tarioba) archaeological site were investigated in order to produce a reference inventory of this taxonomic group. Information on past crustacean diversity is important for establishing baselines on biodiversity, as well as recovering paleoenvironmental information and comprehension of evolutionary change patterns for the Brazilian coast. The archaeological site was excavated by delayering the soil by artificial 10 cm sections which revealed five archaeological stratigraphic layers. A sample of mollusk shells for each of these layers was used for dating based on the C14 method. The results show an occupation period of 550 yr for the Tarioba shell mound, with dates ranging between 4,070 cal BP (beginning of occupation) and 3,520 cal BP (occupation ending) and record nine species of crustaceans from the shell mound. However, a reduction of biodiversity over time was found that was not statically significant. Therefore, it seems that patterns of composition, richness and distribution of crustaceans have been stable in the last 4,070 years BP.

Full-section otolith microtexture imaged by local-probe X-ray diffraction

2018 ◽  
Vol 51 (4) ◽  
pp. 1182-1196 ◽  
Author(s):  
Phil K. Cook ◽  
Cristian Mocuta ◽  
Élise Dufour ◽  
Marie-Angélique Languille ◽  
Loïc Bertrand
Keyword(s):  
A Priori ◽  
Diffraction Method ◽  
Time Frame ◽  
Climatic Conditions ◽  
Structure Characterization ◽  
Fish Stock ◽  
Stock Management ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fish Otoliths

An optimized synchrotron-based X-ray diffraction method is described for the direct and efficient measurement of crystallite phase and orientation at micrometre resolution across textured polycrystalline samples of millimetre size (high scale dynamics) within a reasonable time frame. The method is demonstrated by application to biomineral fish otoliths. Otoliths are calcium carbonate accretions formed in the inner ears of vertebrates. Fish otoliths are essential biological archives, providing information for individual age estimation, the study of population dynamics and fish stock management, as well as past environmental and climatic conditions from archaeological specimens. Here, X-ray diffraction mapping is discussed as a means of describing the mineralogical structure and microtexture of otoliths. Texture maps could be generated with a fewa priorihypotheses on the aragonitic system. Full-section imaging allows quantitative intercomparison of crystal orientation coupled to microstructural description, across the zones of the otoliths that represent distinctive mineral organization. It reveals the extents of these regions and their internal textural structure. Characterization of structural and textural correlations across whole images is therefore proposed as a complementary approach to investigate and validate the local in-depth nanometre-scale study of biominerals. The estimation of crystallite size and orientational distribution points to diffracting domains intermediate in size between the otolith nanogranules and the crystalline units, in agreement with recently reported results.

Characterization of Granite Waste for Incorporation in Red Ceramic

2005 ◽  
Vol 498-499 ◽  
pp. 728-733 ◽  
Author(s):  
Carlos Maurício Fontes Vieira ◽  
Sérgio Neves Monteiro
Keyword(s):  
Thermal Analysis ◽  
Chemical Composition ◽  
Size Distribution ◽  
Rio De Janeiro ◽  
X Ray Diffraction ◽  
X Ray ◽  
Particles Size Distribution ◽  
Granite Powder ◽  
Alkaline Oxides

This work had as its objective the characterization of a granite powder waste from sawing operations with a view to its incorporation in red ceramic. The granite waste came from the municipal area of Santo Antônio de Pádua, State of Rio de Janeiro, Brazil. The characterization was performed in terms of chemical composition, particles size distribution, X-ray diffraction and thermal analysis (DTA/TG). The results indicate that the granite waste presents favorable characteristics for incorporation in red ceramic compositions due to its fine granulometry as well as a considerable fluxing potential related to its high amount of alkaline oxides.

Heat Curing and Delayed Ettringite Formation

1994 ◽  
Vol 370 ◽  
Author(s):  
M.C. Lewis ◽  
Karen L. Scrivener ◽  
S. Kelham
Keyword(s):  
Heat Treatment ◽  
Elevated Temperature ◽  
X Ray Diffraction ◽  
Delayed Ettringite Formation ◽  
X Ray ◽  
Preliminary Results ◽  
Ettringite Formation ◽  
Heat Curing ◽  
Xrd Studies ◽  
Over Time

AbstractThis paper reports some preliminary results from a study of the effect of elevated temperature curing on mortars and the phenomenon of delayed ettringite formation (DEF). Mortars made from cements with sulphate levels of 3%, 4%, and 5% and with 5% sulphate and added alkali were cured at 20 and 90° C and subsequently stored in water. Expansion measurements showed a pessimum effect with increasing S03 content. Mortars which expanded showed a corresponding decrease in strength. X-ray diffraction (XRD) studies indicated that no ettringite is present after heat treatment but re-forms over time within the material. However, the ultimate levels of ettringite reached do not correspond to the magnitude of expansion observed. X-ray microanalysis shows that immediately after the heat treatment the aluminate species and most of the sulphate species are incorporated within the C-S-H gel. The concentrations of these species decrease during expansion, such that at the end of expansion the amounts remaining correspond to the presence of AFm phase mixed with C-S-H.

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