scholarly journals Raman Study on Pompeii Potteries: The Role of Calcium Hydroxide on the Surface Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Daniele Chiriu ◽  
Pier Carlo Ricci ◽  
Andrea Polcaro ◽  
Paolo Braconi ◽  
David Lanzi ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Calcium Carbonate ◽  
Surface Treatment ◽  
Calcium Hydroxide ◽  
Archaeological Site ◽  
Ambient Conditions ◽  
Cooking Process ◽  
Raman Study

Pottery samples from the Pompeii archaeological site were investigated by IR Raman spectroscopy and EDAX measurements. The analysis of the Raman spectra of the surfaces reveals the presence calcium hydroxide (peak at about 780 cm−1) while the calcium carbonate is totally absent. The comparative studies on the carbonation effect of the surfaces were performed on laboratory grown samples of calcium hydroxide. The samples were treated at high temperature and exposed to different ambient conditions, and the analysis suggests that the original surfaces of Roman pottery were scattered by calcium hydroxide (limewash) before the cooking process in the furnace. The result of this surface treatment not only permits a vitrification of the surfaces but also seems to reduce the content of CO2in the furnace atmosphere and then obtain a more oxidant ambient during the cooking of the pottery. These results give new insights on the real degree of knowledge of the Romans about the art of ceramics and more generally about chemistry and technologies.

scholarly journals A hydrated crystalline calcium carbonate phase: Calcium carbonate hemihydrate

Science ◽  
2019 ◽  
Vol 363 (6425) ◽  
pp. 396-400 ◽  
Author(s):  
Zhaoyong Zou ◽  
Wouter J. E. M. Habraken ◽  
Galina Matveeva ◽  
Anders C. S. Jensen ◽  
Luca Bertinetti ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Cement Industry ◽  
Industrial Processes ◽  
Magnesium Ions ◽  
Monoclinic Structure ◽  
Ambient Conditions ◽  
Amorphous Calcium Carbonate ◽  
Hydrated Crystal ◽  
Global Carbon

As one of the most abundant materials in the world, calcium carbonate, CaCO3, is the main constituent of the skeletons and shells of various marine organisms. It is used in the cement industry and plays a crucial role in the global carbon cycle and formation of sedimentary rocks. For more than a century, only three polymorphs of pure CaCO3—calcite, aragonite, and vaterite—were known to exist at ambient conditions, as well as two hydrated crystal phases, monohydrocalcite (CaCO3·1H2O) and ikaite (CaCO3·6H2O). While investigating the role of magnesium ions in crystallization pathways of amorphous calcium carbonate, we unexpectedly discovered an unknown crystalline phase, hemihydrate CaCO3·½H2O, with monoclinic structure. This discovery may have important implications in biomineralization, geology, and industrial processes based on hydration of CaCO3.

The key role of micro-Raman spectroscopy in the study of ancient pottery: the case of pre-classical Jordanian ceramics from the archaeological site of Khirbet al-Batrawy

2014 ◽  
Vol 25 (5) ◽  
pp. 881-893 ◽  
Author(s):  
Laura Medeghini ◽  
Silvano Mignardi ◽  
Caterina De Vito ◽  
Danilo Bersani ◽  
Pier Paolo Lottici ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Archaeological Site ◽  
Ancient Pottery ◽  
Micro Raman Spectroscopy

scholarly journals Coral resistance to ocean acidification linked to increased calcium at the site of calcification

2018 ◽  
Vol 285 (1878) ◽  
pp. 20180564 ◽  
Author(s):  
T. M. DeCarlo ◽  
S. Comeau ◽  
C. E. Cornwall ◽  
M. T. McCulloch
Keyword(s):  
Raman Spectroscopy ◽  
Calcium Carbonate ◽  
Coral Reefs ◽  
Ocean Acidification ◽  
Pocillopora Damicornis ◽  
Seawater Ph ◽  
Ph Conditions

Ocean acidification threatens the persistence of biogenic calcium carbonate (CaCO 3 ) production on coral reefs. However, some coral genera show resistance to declines in seawater pH, potentially achieved by modulating the chemistry of the fluid where calcification occurs. We use two novel geochemical techniques based on boron systematics and Raman spectroscopy, which together provide the first constraints on the sensitivity of coral calcifying fluid calcium concentrations ( ) to changing seawater pH. In response to simulated end-of-century pH conditions, Pocillopora damicornis increased to as much as 25% above that of seawater and maintained constant calcification rates. Conversely, Acropora youngei displayed less control over , and its calcification rates strongly declined at lower seawater pH. Although the role of in driving calcification has often been neglected, increasing may be a key mechanism enabling more resistant corals to cope with ocean acidification and continue to build CaCO 3 skeletons in a high-CO 2 world.

The role of phlogopite in the deep Earth’s water and fluorine cycles

2020 ◽  
Author(s):  
Jiaqi Sun ◽  
Yan Yang ◽  
Qunke Xia
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Powder Diffraction ◽  
Experimental Studies ◽  
Accessory Mineral ◽  
X Ray ◽  
Deep Earth ◽  
The Stability

<p>    Knowledge of the volatiles cycles is vital to understand the evolution of the planet Earth and the life it supports. Although it is gradually accepted that water and other volatiles are recycled into the mantle through subduction, it is still not unclear how these volatiles are transported down into the deep Earth. Phlogopite is an accessory mineral frequently observed in samples from the upper mantle, thereby acting as an important carrier of fluorine and water down to >200 km depth. Previous experimental studies and textural relationships of natural samples have indicated that fluorine-rich phlogopite can be stable under ultra-high-temperature conditions. To further investigate effects of fluorine on the stability of phlogopite, here, we present an atomic level research of effects of fluorine on the structural stability using in situ high temperature infrared spectroscopy, Raman spectroscopy, and X-ray powder diffraction. Both X-ray powder diffraction and Raman spectroscopy suggests that fluorine-poor phlogopite decomposes earlier than the fluorine-rich phlogopite. Moreover, the O-H bonds and lattice modes are stiffer for the fluorine-rich phlogopite than the fluorine-poor phlogopite, which is well responsible for the mechanism of fluorine stabilizing phlogopite. Based on our studies, we propose that fluorine-rich phlogopite can effectively transport water and fluorine to the deep Earth.</p>

Exploring the Biological Protective Role of Carotenoids by Raman Spectroscopy: Mechanical Stress of Cells

2019 ◽  
Vol 64 (1-2) ◽  
pp. 75-82
Author(s):  
F. Nekvapil ◽  
◽  
Cs. Müller Molnár ◽  
S. Tomšić ◽  
S. Cintă Pinzaru ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Mechanical Stress ◽  
Protective Role

ALLEGHENY LUDLUM AL276

Alloy Digest ◽  
1996 ◽  
Vol 45 (1) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Power Plant ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Crevice Corrosion ◽  
Heat Treating ◽  
Chemical Plants ◽  
Temperature Performance

Abstract Allegheny Ludlum AL276 is widely used in the most severe environments found in chemical plants and in power plant desulfurization systems. The high molybdenum level with tungsten gives excellent pitting and crevice corrosion resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, joining, and surface treatment. Filing Code: Ni-497. Producer or source: Allegheny Ludlum Corporation.

NILO ALLOY 36

Alloy Digest ◽  
1987 ◽  
Vol 36 (8) ◽  
Keyword(s):  
Thermal Expansion ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Constant Coefficient ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Temperature Performance ◽  
Iron Nickel

Abstract NILO alloy 36 is a binary iron-nickel alloy having a very low and essentially constant coefficient of thermal expansion at atmospheric temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Fe-79. Producer or source: Inco Alloys International Inc..

UNITEMP N-155

Alloy Digest ◽  
1971 ◽  
Vol 20 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Wide Temperature Range ◽  
Heat Treating ◽  
Combustion Chambers ◽  
Temperature Performance ◽  
Oxidation And Corrosion

Abstract UNITEMP N-155 is an iron-base austenitic alloy used over a wide temperature range from subzero to about 1800 or 1900 F. It has relatively good oxidation and corrosion resistance. It is used in such applications as turbine rotors, shafts and blades, afterburner parts, nozzles and combustion chambers. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness, creep, and fatigue. It also includes information on high temperature performance as well as forming, heat treating, joining, and surface treatment. Filing Code: Fe-48. Producer or source: Cyclops Corporation.

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