Calcium Deposits in the Crayfish, Cherax quadricarinatus: Microstructure Versus Elemental Distribution

2016 ◽  
Vol 22 (1) ◽  
pp. 22-38 ◽  
Author(s):  
Gilles Luquet ◽  
Yannicke Dauphin ◽  
Aline Percot ◽  
Murielle Salomé ◽  
Andreas Ziegler ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Thin Layers ◽  
Organic Layer ◽  
Elemental Distribution ◽  
Edge Structure ◽  
Cherax Quadricarinatus ◽  
X Ray ◽  
Scanning Electron

AbstractThe crayfish Cherax quadricarinatus stores calcium ions, easily mobilizable after molting, for calcifying parts of the new exoskeleton. They are chiefly stored as amorphous calcium carbonate (ACC) during each premolt in a pair of gastroliths synthesized in the stomach wall. How calcium carbonate is stabilized in the amorphous state in such a biocomposite remains speculative. The knowledge of the microstructure at the nanometer level obtained by field emission scanning electron microscopy and atomic force microscopy combined with scanning electron microscopy energy-dispersive X-ray spectroscopy, micro-Raman and X-ray absorption near edge structure spectroscopy gave relevant information on the elaboration of such an ACC-stabilized biomineral. We observed nanogranules distributed along chitin-protein fibers and the aggregation of granules in thin layers. AFM confirmed the nanolevel structure, showing granules probably surrounded by an organic layer and also revealing a second level of aggregation as described for other crystalline biominerals. Raman analyses showed the presence of ACC, amorphous calcium phosphate, and calcite. Elemental analyses confirmed the presence of elements like Fe, Na, Mg, P, and S. P and S are heterogeneously distributed. P is present in both the mineral and organic phases of gastroliths. S seems present as sulfate (probably as sulfated sugars), sulfonate, sulfite, and sulfoxide groups and, in a lesser extent, as sulfur-containing amino acids.

Synthesis of Precipitate Calcium Carbonate with Variation Morphology from Limestone by Using Solution Mixing Method

2019 ◽  
Vol 966 ◽  
pp. 200-203
Author(s):  
Zaenal Arifin ◽  
Triwikantoro ◽  
Bintoro Anang Subagyo ◽  
Mochamad Zainuri ◽  
Darminto
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Molar Ratio ◽  
Mixing Process ◽  
X Ray Diffraction ◽  
Precipitate Calcium Carbonate ◽  
X Ray ◽  
Mixing Method ◽  
Scanning Electron

Abstract. In this study, the CaCO3 powder has been successfully synthesized by mixing CaCl2 from natural limestone and Na2CO3 in the same molar ratio. The mixing process of solutions was carried out by employing the molar contents of 0.125, 0.25, 0.375 and 0.5M at varying temperatures of 30, 40, 60 and 80ᴼC. The produced CaCO3 microparticles were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The highest content of aragonite phase with morphology rod-like of the samples is around 29 wt%, resulting from the process using solution of 0.125 M at 80 ᴼC. While at 30 ᴼC and 40 ᴼC produced 100 wt% calcite phase.

Eyeing the past: synchrotron µ-XANES and XRF imaging of tarnish distribution on 19th century daguerreotypes

2019 ◽  
Vol 26 (5) ◽  
pp. 1679-1686 ◽  
Author(s):  
M. S. Kozachuk ◽  
T. K. Sham ◽  
R. R. Martin ◽  
A. J. Nelson ◽  
I. Coulthard
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Synchrotron Radiation ◽  
National Gallery ◽  
Edge Structure ◽  
X Ray ◽  
The Past ◽  
National Gallery Of Canada ◽  
X Ray Absorption ◽  
Scanning Electron

Louis-Jacques-Mandé Daguerre introduced the first successful photographic process, the daguerreotype, in 1839. Tarnished regions on daguerreotypes supplied by the National Gallery of Canada were examined using scanning electron microscopy energy-dispersive X-ray spectroscopy and synchrotron-radiation analysis. Synchrotron X-ray fluorescence imaging visualized the distribution of sulfur and chlorine, two primary tarnish contributors, and showed that they were associated with the distribution of image particles on the surface. X-ray absorption near-edge structure spectroscopy determined the tarnish to be primarily composed of AgCl and Ag2S. Au2S, Au2SO4, HAuCl4 and HgSO4 were also observed to be minor contributors. Environmental contamination may be a source of these degradation compounds. Implications of these findings will be discussed.

scholarly journals Nacre morphology and chemical composition in Atlantic winged oyster Pteria colymbus (Röding, 1798)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11527
Author(s):  
Pablo Santana ◽  
Dalila Aldana Aranda
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Organic Matrix ◽  
Carbonyl Groups ◽  
X Ray Diffraction ◽  
Mineral Phase ◽  
X Ray ◽  
Minor Elements ◽  
Scanning Electron

The microstructure and nanostructure of nacre in Pteria colymbus were studied with high-resolution field emission scanning electron microscopy (FESEM). The tablets were found to be flat and polyhedral with four to eight sides, and lengths ranging from 0.6 to 3.0 µm. They consisted of nanocrystals 41 nm wide, growing in the same direction. X-ray diffraction showed the crystals to be mineral phase aragonite, which was confirmed by Raman spectroscopy. Fourier transform infrared spectroscopy identified a band at 1,786.95 cm−1 attributed to carboxylate (carbonyl) groups of the proteins present in the organic matrix as well as bands characteristic of calcium carbonate. X-ray fluorescence showed the nacre to contain 98% calcium carbonate, as well as minor elements (Si, Na, S and Sr) and trace elements (Mg, P, Cu, Al, Fe, Cl, K and Zn).

Influence of Inorganic Ion on the Synthesis of Hollow Calcium Carbonate

2006 ◽  
Vol 11-12 ◽  
pp. 677-680 ◽  
Author(s):  
Gunawan Hadiko ◽  
Yong Sheng Han ◽  
Masayoshi Fuji ◽  
Minoru Takahashi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Room Temperature ◽  
Hollow Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inorganic Ion ◽  
Potential Component ◽  
Scanning Electron

Hollow calcium carbonate (CaCO3) particles were synthesized by bubbling CO2 in the solution of calcium chloride (CaCl2) with the presence of ammonia at room temperature. Hollow calcium carbonate is a potential component to be used as pharmaceuticals, agrochemicals, and catalysis. This paper investigated the effect of additive on the hollow structure. In this study was used vanadate ion as additive agent. Physical characteristics of precipitate were evaluated using scanning electron microscopy (SEM) and X-ray diffraction (XRD).

Preparation of Electroless Ni-Mo Coated TiC Powder

2010 ◽  
Vol 434-435 ◽  
pp. 522-525
Author(s):  
Wu Peng ◽  
Yong Zheng ◽  
Quan Yuan ◽  
Hai Zhou Yu ◽  
Shao Gang Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thin Layers ◽  
Surface Microstructure ◽  
X Ray ◽  
Unknown Phase ◽  
Supersaturated State ◽  
Diffraction Peaks ◽  
Electroless Ni ◽  
Scanning Electron

Ni-Mo coated TiC powders were prepared by electroless plating technique assisted by ultrasonic wave with hydrazine as reducing agent. The surface microstructure of the Ni-Mo coated TiC powders was characterized with scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). The results showed that the as-plated powders, which were of nearly spheric shape, were the composite of TiC and Ni-Mo alloy. The Ni and Mo elements were uniformly distributed around the TiC powders with some plating leakage. In addition, the Ni-Mo plated thin layers on the surface of TiC powders were amorphous or microcrystalline in a supersaturated state. Diffraction peaks corresponding to Ni and Mo weren’t found, and the Ti (NO3)4 and an unknown phase were formed as the load decreased from 15 g/L to 5 g/L.

Influence Factors of Calcium Carbonate Whiskers Prepared by Intermittent Bubbling Method

2013 ◽  
Vol 310 ◽  
pp. 80-84 ◽  
Author(s):  
Bei Ping Liu ◽  
Jian Chen ◽  
Fang Bo Liu ◽  
Shi Biao Zhou ◽  
Yuan Dao Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Aspect Ratio ◽  
Smooth Surface ◽  
Influence Factors ◽  
Large Aspect Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Calcium carbonate whiskers were successfully prepared in the MgC12-Ca(OH)2-CO2 system by a intermittent bubbling method and characterized by X-ray diffraction and scanning electron microscopy. The results demonstrated that aragonite style calcium carbonate whiskers with well morphology, large aspect ratio and smooth surface can be obtained by controlling technical conditions such as reaction temperature, concentration of Ca(OH)2 and amount of additives and under the conditions of CO2 flow velocity of 3.4ml/min/gCa(OH)2, flow of CO2 to air ratio of 1:4, stirring speed of 240 r/min.

Mechanical and tribological studies of sintered nickel-based ternary alloys

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bukola Joseph Babalola ◽  
Ojo Jeremiah Akinribide ◽  
Olukayode Samuel Akinwamide ◽  
Peter Apata Olubambi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ternary Alloys ◽  
Tribological Characteristics ◽  
Indentation Hardness ◽  
Elemental Distribution ◽  
Content Type ◽  
X Ray ◽  
Mechanical And Tribological Characteristics ◽  
Scanning Electron

Purpose During the operation of nickel-based alloys as blades and discs in turbines, the sliding activity between metallic surfaces is subjected to structural and compositional changes. In as much as friction and wear are influenced by interacting surfaces, it is necessary to investigate these effects. This study aims to understand better the mechanical and tribological characteristics of Ni-17Cr-10X (X = Mo, W, Ta) ternary alloy systems developed via spark plasma sintering (SPS) technique. Design/methodology/approach Nickel-based ternary alloys were fabricated via SPS technique at 50 MPa, 1100 °C, 100 °C/min and a dwell time of 10 mins. Scanning electron microscopy, X-Ray diffraction, energy dispersive X-ray spectroscopy, nanoindentation techniques and tribometer were used to assess the microstructure, phase composition, elemental dispersion, mechanical and tribological characteristics of the sintered nickel-based alloys. Findings The outcome of the investigation showed that the Ni-17Cr10Mo alloy exhibited the highest indentation hardness value of 8045 MPa, elastic modulus value of 386 GPa and wear resistance. At the same time, Ni-17Cr10W possessed the least mechanical and wear properties. Originality/value It can be shown that the SPS technique is efficient in the development of nickel-based alloys with good elemental distribution and without defects such as segregation of alloying elements, non-metallic inclusions. This is evident from the scanning electron microscopy micrographs.

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