scholarly journals Utilizing optical spectroscopy and 2´,7´-difluorofluorescein to characterize the early stages of cement hydration

Author(s):  
Jutta Pauli ◽  
Alejandra. Ramírez ◽  
Claudia Crasselt ◽  
Wolfram Schmidt ◽  
Ute Resch-Genger
2016 ◽  
Vol 129 ◽  
pp. 11-24 ◽  
Author(s):  
Hamed Asgari ◽  
Aliakbar Ramezanianpour ◽  
Hans-Jürgen Butt

2011 ◽  
Vol 105 (2) ◽  
pp. 625-633 ◽  
Author(s):  
Maura B. M. Melchert ◽  
Marcelo M. Viana ◽  
Mariana S. Lemos ◽  
Jo Dweck ◽  
Pedro M. Büchler

Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.


Author(s):  
S. Mahajan

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.


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